The Orange Box (and the Black Box?) are scheduled for release in October, with TF2 in them.
Psycho, I know you hate the source netcode, but TF2 is designed to be silly and fun. In fact, it can be argued that aiming is not required, and high ping / anti-lag should have little effect, because in the case of many weapons firing near the enemy is just as good as at the enemy.
While it will probably be less explosive spam than TF/TFC (Less grenades, no Incendiary launcher *cry*, it should not be a problem.
In fact, I'd argue the following classes, with a half-decent connection, are fully playable
1) Demo Guy
2) Medic
3) HWGuy
4) Pyro
5) Spy
6) Engineer.
The engineer could be played *somewhat effectively* with uber-bad connections, and because of how the spy seems to work, the same is true.
Only the Soldier and the Sniper really seem to require much precision (arguable about the soldier, but they say getting direct rocket hits is more important than previous games) where as the scout could suffer to lag and anti-lag measures as they may make him easier to hit, and getting hit at all is a death sentence.
Overall, the only thing i find worrying is there only being 1 CTF map in the original release. While I find the other maps interesting (I think they are going for 1 map of every play style) I just think TF was always best with thoughtful well designed CTF maps (don't know if anybody played much, but 2fort, well, and badlands stick out as great CTF maps.)