I’ve never done anything in a game purely for xp, unless you count the challenges in Brink - basically if you need to dangle the carrot of xp to make folk do things then the core game lacks something.
Again go back to RTCW - no xp, yet we still had engies blowing things up, medics reviving, lts handing out ammo and soldiers annoying folk (pf / snipers). All without the apparent need for convoluted ingame context based vsay/mission creators that are never going to be used by the majority of the pub players. As for clan players using it, that’s really far fetched, considering they would have assigned classes and map strats laid out in advance…