it was interesting to see not only how it tends to enhance the character of the classes, but i'd swear it effects my play style and the tone of the players around me in the game.
at times it can make encounters more entertaining. when i was playing the heavy, i'd run forward and he'd chuckle confidently and shout "I FEEL ALIVE!". when i'd pullback to dodge a rocket or retreat from an enemy push, sometimes my character's last words would be "NOT GOOD!" as an arrow planted itself in my skull.
when i played the scout, he would laugh joyfully as he jumped all around their heads trying to dodge attacks and if i manage to kill them in the process, the next time we crossed paths, they tend to quickly adjust their priorities. i think the scout's arrogance definitely aggravates players. after a while they really start to come at me when I enter the same room as them.
the medic runs faster than the heavier attack classes and so i'm often running ahead, looking backwards, watching for spies or teammates low on health. this play style makes my medic say more negative things than the others. often times i'll glance back at someone i'm paired with and the script berates them on a subconscious level. my medic shouts "MNAAH!" and "Dummkopfs!" and coincidentally i've notice their weapon will sometimes drop, meaning they've lowered their view towards the ground or will leave me behind by taking a different route.
because there is so much action going on in game, there is already automatic emotes being cued from everywhere in the game so it's ingrained into the experience. there are pained cries or gruffs from get-hits and sometimes a player might battle cry at the start of a round or say, "The cart's going backwards!" or "Help me capture this point!". most players will often use these emotes to call for medics or out a spy or simply thank people. then text chat and mic chatter sandwiches another level of noise on top of this digital stew of expression.
the spy is snarky and his attitude, like all of the classes, is portrayed in his voice commands. not so much "trolling" but i felt like more shit talk started when his emotes were being spammed as i ran around the level.
people seemed to enjoy the presence of the soldier barking his orders at them. on the server i played on, players would actually mimic his laughter. it seemed fairly obvious to me. it reminded me of when observing gears of war players mimicking the catch-phrases from the game while they played.
i think everyone got quieter when i played the pyro. he makes these muffled giggles and friendly chirping sounds from behind his death mask. and the fact i was running forward most the time exuded a softly spoken, nice, and positive ambiance, until my enemies began screaming through a blanket of flames.
the script broke down for the engineer. it turns out he only has 1 positive clip: "Well don't that beat all!" so i'd be running around saying that a million times in a row annoying the shit out of everyone, including myself. the tf2 wiki scripting page says you can make class specific config file, ie. engineer.cfg
so maybe i can just make him constantly say "Somebody wanna wrastle up a... teleporter 'round here?" and "We need a teleporter riiight here."
i had to remove it from my config after an hour but it was really interesting. i'll have to modify the script so the voice commands have a pause and are more spaced out to remove the burn out aspect.