Sounds more like an idea for an RTS. I think you should tell Petroglyph games to make EAW2 like that!
TF2 was very, very violent and not that cartoony, just an art direction, but I wouldn't want my children to see soldiers getting bonesawed or blown up!
As for technology, how many polys are the modern fps games using?!?! Seriously, if they weren't so obsessed with making the butts of the female chars so smooth you could have thousands of characters on screen easy, as early PS2/XboX games demonstrated. Cell shaded games are generally low poly anyway so with modern tech it'd be a breeze.
I am the definition of your defeat.