Personal recommended changes for each legend.

Here is a suggested list of changes for each legend:

Ash:

The thing I see most about Ash players is they barely ever use their passive. Their tactical is extremely strong, its practically a death sentence if used on anyone trying to flee that is closer than sniping range. Her ult as well is doing just fine.

• Update passive to be an item stored in inventory (team location chip). Item has a 3 minute cooldown but can be used at any time as many times as you want. Chips remove themselves from your inventory if the team is killed. Each team chip takes an inventory slot and can be dropped at will. Only Ash players can use these chips.

Bangalore:

Bangalore is honestly in a  good place, her Ult could use some QOL.

• Holding the button with Ult displays the missile path.

Bloodhound:

Bloodhound's ult and tactical are strong, but the passive is a bit lacking.

• Increase the range at which tracks are visible

Caustic:

Caustic is in a pretty terrible place. He lives inside or he dies outside. His tactical is just a nuisance, his passive is rarely useful, and his Ult is about the only part of his kit that is useful.

• Swap his tactical and ultimate
• Make the gas grenades more like bangalore gas, but are capable of doing damage under the right circumstances.
• Ultimate applies stacks of toxin, causing enemies in any gas to take damage based on how many stacks they have. The more they are exposed to the traps, the more stacks they get. Destroying the traps rather than disabling causes them to turn into a gas grenade effect that also applies 1 toxin stack.
• Passive is applied to all teammates when an enemy is in gas with toxin stacks. Caustic can see anyone in his gas even without stacks if he is in the gas too.

Crypo:

Crypo suffers from being both too tedious to use, and punished for being useful. His passive and ult are all tied to a drone with an egregiously long destroyed cooldown.

• Remove drone destroyed cooldown, drone now auto-recalls when damaged at 1 hp. Drone regains HP when stored.
• Deploying the drone deploys it into a follow mode, giving Cryto the ability to see billboard counts. Drone follows his movements. EMP can be used in follow mode. When in follow mode:
• Pressing tactical in open air sends the drone to open air like normal.
• Pressing tactical on a surface sends the drone to sentry mode like normal.
• Pressing tactical on a teammate sends the drone to follow the teammate.
• Pressing tactical outside of follow mode causes the drone to manually fly back to you into follow mode.
• Passive Change: Crypto's drone remains active when downed. If Crypto is boxed his banner is automatically collected.

Fuse:

Fuse is in a good spot, only issue I see is his inventory management is pretty difficult. His tactical is great, his ult is a good suppression weapon, not for damaging like some people think.

• Passive Update: Fuse can stack 3 grenades.

Gibraltar:

Gibby is in a bad place, and has been since season 0. The only thing that changed was the pro-meta that revolved around his tactical. The moment it got nerfed, he fell from grace. His passive is peanuts in comparison to his hitbox, his tactical is a beacon that says "please rush me", and his ult honestly feels out of place for a defensive character, but honestly not worth the effort complaining about it.

• Passive update: Gibby can charge his gunshield with two shield cells, giving the shield a 50hp buff that does not regenerate.
• Tactical rework: Tactical buffs Gibby's gunshield, giving it 400 additional hp, spreading out its range so that two teammates can shoot through it at his sides, and the gunshield remains always on until destroyed or turned off manually, allowing you to use items or blindfire. While tactical is active Gibby's unarmed sprint speed is reduced to weapon up sprint speed.

Horizon:

Horizon is one of those characters only useful to people with excellent aim, resulting in her being a hyper niche character. To make her less hyper niche, she needs the most exploitable part of her kit nerfed.

• Tactical change: Being in tactical dramatically reduces your accuracy to that of zipline firing until you land. Tactical cooldown is reduced, tactical rise speed increased. 
• Ultimate buff: Increase ultimate range, pull strength is reduced based on distance to center.

Lifeline:

Lifeline is in a decent place. Her passive is acceptable, but could use a bit of a situational buff. Her tactical is highly useful, and her ult needs a touch up.

• Passive buff: If her tactical is available, using her passive will automatically consume the tactical cooldown, causing the revive drone to heal the HP of the downed player while they are being revived. After the revive is complete, the drone remains in place as a tactical drone. If her tactical is on cooldown, it is the same as it is now.
• Ultimate buff: Weapon attachments, helmets, knockdowns, and bodyshields given will all be epic or greater.

Lobra:

Her tactical and ult are good, but her passive is often underutilized, specially given equipment in boxes is not visible. So I suggest a new useful addition to her passive:

• Passive buff: While unarmed, you can use your staff to steal teammates banners and "mark" their boxes. Requires you to go through a 5 second charge up to steal a banner, causes a "steal item" effect trailing back to you. You can "mark" boxes even if the banner is already collected.
• Mark effect: Teammates can teleport their deathbox to their location through a black market choice at any range so long as their deathbox is marked.

Mad Maggie:

Honestly she is doing just fine, a little surprised she is not octane level popular given she does nearly the same. Her only issue is not even related to herself, her issue is that she is a bunker buster, in a game with so very few effective bunker characters.

• Buff bunker characters to make her more useful.

Mirage:

Mirage suffers from a high skill ceiling with not so high of a reward. He could use some more accessibility.

• Passive buff: Revives have 1/2 audio range and are completely invisible.
• Tactical buff: Decoys are easier to distinguish and less visually cluttering for teammates (and less audio callouts..) Decoys under direct control aim where you are aiming and imitate your gunfire, firing harmless rounds that converge on where you are aiming. Decoys are destroyed after 50hp of damage.
• Ultimate buff: Decoys spawn with NPC ai doing an assortment of random actions. Some will aim and fire at nearby enemies with harmless rounds, some will run off into the distance, some will hide and take cover, some will taunt with eachother.

Newcastle:

Truly a victim of the pro mindset, as pros have managed to twist him into a gibby replacement, hence his plat 4 average, just like horizon and seer. Newcastle needs to be dragged back into his intended purpose and out of this pro specific niche hood.

• Undo all changes of S14.
• Passive buff: Newcastle can use healing items in inventory to charge a revive specific health and shield pool. He has to use the item to completion to fill the pool. On revive, the ally is fed health and shields during the revive (meaning if the revive is canceled half way through, the downed player still gets 100(knocked down)hp and 100shields healed. The effect is like a mixture of wattson's charge and lifeline's drone, but it is at his expense.)

Octane:

Honestly he is in a great place, only he encourages a bad behavior by his nature. I don't really see that as an issue though, its self inflicted.

Pathfinder:

Pathfinder's only real weakness is his passive, which is definitely sorely in need of help.

• Passive overhaul: Pathfinder starts the game revealing the first ring location. Accessing a survey beacon will unveil not just the next ring, but the next ring after that one.

Rampart:

Rampart as well suffers from some nichehood, given how button heavy her cover is. Her passive is almost completely trivial given most people do not deploy her turret anymore, and you are discouraged from using a machinegun given she gets one for free. Her tactical could use some cover work, given only the top portion is all that useful, but I don't think its that big of a deal.

• Passive overhaul: Rampart uses the exo-holder on her back to attach to any light machine gun she uses, reducing all machine gun recoil and bullet spread (no effect on Ultimate, as it is already affected with great recoil and spread). This will allow rampart to use LMGs as a more all purpose weapon (having the lack of recoil for long range [cough L-star] and the lack of bullet spread for point blank blindfire [cough spitfire].)

Revenant:

Rev suffers from nichehood mostly due to the hit or miss nature of his ult. His tactical is quite strong, but his ult can leave you out to dry, and his passive can often be trivial.

• Passive buff: Rev can now climb up walls for a limited movement duration. He can climb in any direction and hang to the wall.
• Ultimate buff: Ultimate offers a key to be forcefully recalled to the totem. Teammates in ult are given threat vision.

Seer:

Seer is a little too good, given his all direction vision is great for teams with comms, but ultimately not very user friendly to players without voice chat.

• Passive no longer sees players that are standing still or crouching and not shooting.
• Pinging an orange mark in passive places an "enemies have been there" mark somewhere within a ballpark of the orange mark's target. Location is not exact. Ping has a cooldown.

Valkyrie:

Valk is honestly a mixed bag, her tactical is amazing, her passive can be useful, but her ult is very hit or miss.

• Tactical nerf: Remove the slow and stun effect.
• Ultimate buffs: Reduce Ultimate cooldown by 50%. Add a "solo flight" mode that disables teammate flight, but dramatically reduces the noise and delay before liftoff.

Vantage:

Vantage came out the gate swinging, and it shows. Her ult is basically a long range rampart ult and it does a better job of suppressing enemy pushes than Caustic does with his whole kit. Her tactical is a free octane pad that is far too easy to use with no downsides, and her passive is good for just about everything.

• Tactical nerf: Echo must be out and in position to jump, the quick jumping is far too easy and beneficial. Echo should force recall when shot at.
• Ultimate nerf: Reduce sniper mark specific 2x buff to a 1.5x damage buff. Reduce bullet count to 4 with same cooldown.

Wattson:

Wattson's biggest issue is the same as casutic. She lives inside or dies outside. Her pylon is extremely trival to teams with mobility legends, often leaving them out in the open to for enemies to benefit from. Allowing her to pick them up for ult charge would not change the fact that her pylons are trivial, it would just allow her to more frequently place trivial pylons.

• Passive buff/nerf: Remove 1hp/s recharge. Buff ult-accelerant stacking to 3.
• Ultimate rework: Like rampart, give Wattson an ability to deploy the pylon on her back. While it is active she can run, but not use weapons or items. Like Vantage, allow the pylon to be activated at 25% charge, and stored to recharge. Her ult should have a built in "charge count" mechanic, intercepting or healing shields uses charges. Allow her ultimate to be buffed by ult-accelerants to go over 100% charge (IE 100 charge regeneratable max, if you use ult-accelerant at ult 50% charge you get 150 charges.) Deploying a pylon will give it the full charges remaining and restart the ult charge process.

Wraith:

Wraith is doing well with her tiny hitbox and mobility skills. I don't really see any issues with her aside from the stigma.