As someone who recently has begun trying to play Wattson, I win a lot of games with her.
But I've literally almost never actually used her tactical. When I go against a Wattson, I've never really gone through her traps. There's a fundamental design problem in Wattson's Kit compared to the rest of the game. It isn't even that her Design is bad, it's mismatched with the rest of the games mechanics.
Visibility, weapons, mobility and building design work very heavily against Wattson.
Visiblity: Wattson camping a building is Obvious, and it doesn't prevent people from seeing you behind those fences.
Weapons: Bullets aren't stopped by the fences so they will just keep shooting at you until you're dead or out of supplies.
Mobility: Flanking a wattson is very easy, especially with these "Low win rate" heroes like Bloodhound and Octane. Good luck setting up defence before the octane is literally already inside.
Building fights usually result in people shooting the living crap out of you through windows. Wattson or not, people with braincells do not face-check buildings.
Proposed changes to Wattsons Kit?
Damage modification when fighting through her fences:
She is a defence character but this game is highly aggressive. Almost every character has a means of augmenting your offense capability except Wattson. Shooting through Wattsons fences can add an electrified status to friendly fire. This can raise damage by a set amount creating benefits to Bunkering.
Conversely to stay within the Spirit of the character, this can also just reduce damage from enemy fire by a certain amount, allowing survivability and creating a better use in a defensive position. People shooting at you through windows? THey'd rather not do that if you're reducing their damage output significantly (And it must be significant, as other characters ability to Immediately chunk or blind players is not just a 10% difference in combat).
Barricade Ultimate Interactions:
in addition to the above interactions, the barricades could be boosted by being in range of the Ult. With an additional caveat of having greatly boosted HP or defence so they are not easily broken. Players attacking a fully bunkered Location should have to commit more.
So More damage being shot through/less incoming damage, and higher HP values (or making barricades only take a small amount of damage)
Ultimate Ability:
Wattsons Ultimate can be super useful, but also super useless. While this is the case with many Legends, it feels a little unfair that your ability isn't really able to be used to kill.
Grenade disable: Wattsons Ability to disable grenades could also do something better. Making them drop as useable grenades. Throwing grenade after grenade into wattsons Ult is not a good idea, but it would be much better for the using-team to have those zapped grenades drop onto the floor. Also whenever you throw a grenade and it gets zapped by your own teams Ult, that allows you to recover your damn zapped grenade.
With this and the barricade changes I almost feel this would make Wattsons Kit a highly beneficial kit, However with how easy it is to charge wattsons Ult, you could turn a few combinations rather toxic. So her passive may need to be reworked.
New Passive:
A few ideas/choices
Use 2 battery packs to charge your melee attacks. Charged melee attack slow opponents like her Barricade
Use # of battery packs to increase damage of a weapon. Number of packs used change based on the weapon type. (Not the best idea)
Use # of battery packs to increase bullet velocity of weapon (Not bullet drop) (This would allow long range engagement efficiency and not necessarily reward bad aim)
Use batteries and Phoenix kits faster.
Personally I'd lean towards the bullet velocity suggestion, simply because Long-range combat suffers a lot and Wattson is pretty poor in long range engagements (In terms of abilities and her design focus) with the Slow melee ability being the next best idea. I'd rather lean away from having too many disabling effects on other players and any abilities that do actively debuff players should be more difficult to use in fire fights. (Melee during a fire fight is ill-advised)
Edit:
As an additional note: These changes are to allow Wattson the ability to BECOME the location of fortification as opposed to Finding places to poorly fortify.