I've recently returned to Team Fortress 2 after yonks away--enjoying the Brit-tastic Rock, Paper, Shotgun TF2 server--and I must say it's delightful to see every class updated. While I'm still not entirely certain what the plethora of guns, swords, knives, axes and chocolate bars do, they certainly shake it all up.
Rivalries are a lot easier to start when most players are unique, too. That opposing demoman with the Chargin' Targe and Eyelander might be zipping past my stickybombs, forcing me to recognise them and treat them differently. Lovely.