Valve knows the #1 complaint is crits. So what do they do? They add even more crit damage with the uber. The only way this new medic weapon works is if they remove the random crits from every player.
But what's wrong with the game? A bunch of things.
1. Brown desert industiral environment in every map. Boring, tedious and unimaginative.
2. Static control points have been a failure(especially in linear maps). This game seriously needs more CTF, some Hunted, some flag-run, etc. The current capture system is boring.
3. Not enough weapons. All too often TF2 turns into Shotgun Wars. And the shotguns aren't all that interesting looking or sounding save for the Scout's. Need more depth.
4. Invisible map walls. Why punish players for trying to be creative and finding new things which extend lifespan of game?
5. Respawn times. These are a crutch. Make the maps bigger and get rid of them. Walking across a map with potential for a skirmish is more fun than sitting in a respawn.
6. Splitting the community with a custom tab and regular tab. Not a smart move.
I'd like to see Valve admit their mistakes and fix some of these problems. TFC was a much more popular game at this point in it's release, and it took FAR less work than this.