I have a love-hate relationship with TF2. I love the focus on teamwork and the cartoony, "Pixar'ish" look of the game, but I hate that Valve has used it as a guinea pig to test out features (trading, crafting, in-game shop, free to play, etc.) which as a result have definitely changed things.
It's not what it used to be, it doesn't look as good, and the average skill level has taken a hit, but at the end of the day it still is TF2. However, the days of playing on any server/map with total strangers are over. I find that I'm only able to enjoy the game when playing on a select few servers with other regulars that I've come to know over the years.
I do miss the days when updates were all about balance changes. Those were good times. Nowadays there's just too many different items that have been affected by power creep that balance is an impossible task at this point, so the game has gone from "playing to win while having fun" to just "playing for fun".