Though Valve likely somewhat cannibalized the Team Fortress 2 fan base with the release of its own, equally excellent Left 4 Dead, there's still pretty fervent interest in big changes and small tweaks coming to the game. The company recently detailed a few of them, like rechargeable cloaking for Spies and the ability to upgrade dispensers and teleporters to level 3.
Valve also revealed that it's working on a Scout expansion next, as well as "a massive Xbox 360 update, which will include pretty much everything shipped on the PC in the last year. " Sadly, there's still no date on the upgrade.