Signature Weapon Bonuses Should Increase Spendable Attachment Points

Absolutely agree with your statement. The issue with their buffs are that the base stats for soldiers is already to high so anything they add is verily noticeable or pointless (Keep in mind BF players have learned to make up for low base stats with their own Personal gaming skills)

As you have pointed out removing the LMG penalty doesn't make a difference as you are running at the same pace as everyone else, there is no class that actually moves slow so we don't have anything to compare it too. To make matters worst the current base pace for players is fast tactical pace (walking) or sprint. Now I'm not saying they need to debuff since we know y they are doing this but what they can do is lower the base stat to what it should be so that each class buff or paths brings their stats up to were we are. This way it better emphasizes each unit and class. Example:

Currently Fire support has steady aim by mounting their weapons which should be useful but you have to sit the weapon on something so you can't move and are an easier target. On the other hand there are some weapons that with the help of attachments they are just as steady but they aren't locked in place. Even if fire support used a better weapon it would render its own ability useless as he no longer needs to sit his weapon to have steadier aim.

What I would propose is lower the base stats so you can raise them by creating synergy on each class. Example:

Fire support (low stats) bad sway and recoil will be negated by signature weapon + path skills + weapon accessories = steady aim

Its rough but if they applied something like this the buffs would make a huge difference with out the need of overcomplicated mechanics. Trial and error would be absolutely necessary to get the feeling right and which stats should be lowered or not

Personally I don't have a problem with the movement speed since movement mechanics have been address but I would like a stamina bar added.

Some stats they can lower are; recoil control, sway control, visual recovery (flash), health regen (activate and refill speed), stamina (currently is infinite),  there are a few more but I think those would work better on hard core

The recent community update has confirmed that the open weapon default is here to stay and has also admitted that, under the open weapons playlist, more players selected weapons that were not signature to their class. In light of this, I feel like it is a good idea to take a deeper dive into looking at how the signature weapon bonuses can be improved to better incentivize players selecting signature weapon choices.

I disagree, if anything the community update proved that the current open system was quite balanced during the beta, and it works well. 

The whole point with this signature bonus is that it should be a very small incentive, and it should not feel mandatory. Having 120 attachments points for signature weapons would be way too much, and it would no longer feel like a choice (depending on the weapon and the available attachments). 

From the article: 

Signature Weapon Usage:

More players played with non-signature weapons in Open Weapon playlists. However, Recon players still favored Sniper Rifles over other weapons, and their pick rate was identical between both playlist types. 

There was not a single dominant weapon archetype, and we observed a consistent and well-distributed pick rate between them. This balance shows that even with different playlist types, players explored a wide variety of options without one class standing out above the rest.

Sounds too me it was a well balanced pick rate. So, no need to change that. Of course they can tweak / balance the bonuses eventually, but it should remain a minor bonus.

With you on that. I would support that during open weapon playlist 

I do not believe 20 attachment points is stronger than the current signature weapon bonuses.

What attachment could the increment of 20 attachment points (after you have already spent 100 attachment points on a weapon and have already equipped most high-priority attachments) afford you that would yield a stronger bonus than any of the current signature weapon bonuses?

In most cases this additional 20 attachment points would only yield a laser sight (which is basically the Engineer's current signature bonus with the added downside of having a visible laser) or an ammo type, or a small upgrade to your foregrip (resulting in only a very small increase to recoil control).

20 attachment points IS a minor bonus. This change primarily gives the player more flexibility in choosing how the signature weapon bonus can benefit them and does not upset the current balance of power.

One could even make the argument that the 20 attachment points I am proposing is actually weaker than the current signature weapon bonuses on account of Recon's signature bonus increasing their fire rate, as there is currently no attachment that accomplishes this. This could be easily solved with the addition of a "quick bolt" weapon attachment, however.

You might be right. It is just a guess from my side.. I admit that. I have obviously not tried all the weapons (other than the weapons available in the beta) and seen all the different builds possible with the attachments, so I don't know. I also think this would be even harder to balance? as it would (at least based on the available attachments during the beta) seem to benefit certain weapons more than others. Hard to tell without actually testing builds with 120 attachment points though.

Having had the chance to play around with the full list of attachments, I definitely do not think the 20 additional attachment points would be overpowered. On most of my builds, I would dedicate the additional points to an upgrade to the foregrip which would yield only an improvement to ADS time or invest in a different ammo type. On my snipers, it would afford me a bipod and the cheapest laser sight.

Regarding your point about the difficulty in balancing this proposal: one of the best things about this suggestion is that it is based completely off of the attachment point system, which requires balancing anyway. In terms of balancing the additional attachment points given by the signature weapon bonus, that would just be a matter of changing the number. If 20 is too much, it could easily be adjusted up or down.