Thank you for pointing out the inanity of having indiscernible character classes from one another.
This is a huge complaint I have with most multiplayer games nowadays, it's that every single one of my opponents look exactly the same. You don't know what weapon they're holding, what perks they have, what abilities they have, or even if they're on your team in some cases until they fire their weapon or you fire on them. And by the time you've offed them, or they offed you, you've already forgotten what skills/weapons/perks they had and move on to the next victim.
I don't mind customization, and I'd imagine the customization in Brink is quite indepth, but it means nothing if I can't tell what weapon/perk/ability my opponent has in a glace. That's what makes TF2 extremely well designed, you look at a Heavy and you instantly know what weapons he can carry and what strategy you need to use against him. You look at a Sniper, you understand what they do and don't excell at. You look at an Engineer and you know that you need to look for a teleporter or watch out for a sentry. Quick, easy, and accessible multiplayer.