Deeper attachment customization means more replayability and a better game.
I like the plus system, it just doesn't allow you to customize your playstyle enough to create different styles of play. This has been my main complaint on BF1 and BFV. I thought the plus system would fix it, but it doesn't even compare to CoD's gunsmith system. You can't really create many different playstyles with the current low gun count and weak attachment customization.
My only complaint about 2042 so far is the lack of versatility with your weapons. CoD's gunsmith system is very good and sets a high standard. You can tweak a weapon exactly how you want it to play, and save presets for your favorite combinations. This is one of the few parts of the newest CoD games that I like, I think they nailed it.
If BF just had fewer options in each category but they achieve the same goal, I'd be happy with that.. you just can't really make a huge impact. A 5% difference won't really change the game, but it makes your experience feel unique and adds more content and replayability overall.
Any gameplay will benefit from more variety. Gunplay and its variety should be a priority in any game where most of your time is spent on the ground, shooting guns. The more variety you can add to that experience, the more content the game will have, it'll be more replayable, and be better in general.
Every gadget and vehicle should have more customization options too, to tweak your gear exactly to your playstyle.