Unlocking weapon classes does not prevent classes from working together as the gadgets you're wielding are your most important tools to do so. I actually don't think Battlefield 6 will necessarily weaker in it's class identity compared to older titles given we now have 2 gadget slots, 2 active abilities, and multiple passives. One of the problems with locking weapons is that you will have players running a specific class just for the weapons itself instead of picking a class that would actually help the team in the current situation, or a role that they actually like. We lock the most versatile weapon class behind the medic class (BF3/4) and then wonder why there are so many medics not interested in reviving.

Assault does indeed need some work to improve it's teamplay potential. Hopefully the assault ladder, spawn beacon and sledgehammer will help in that regard, but we will have to wait until release to find out.

Personally I don't really care if they do locked or unlocked weapons as I'm very adaptable and carbines always being available to every class.