One of the things I liked in Crysis 1/Wars was the easily changeable weapon attachments. We still have this in the C2 campaign, but I would really like it the multiplayer. Yes, you have to level up to spawn with the stuff, but you can pick up whole guns with the higher level attachments, so why not be able to switch them out like in Wars?
If you (Crytek) thinks it would unbalance the game, then add in a short delay each time you add or remove an attachment. That would be more realistic anyway.
Post here if you agree.