I agree that the last UGAC went on for too long, I don’t feel the poly count had much to do with it though.
I like the sound of team entries, though getting a team together in the first place might be difficult, let alone staying together and coordinating.
Doing one thing is a bad idea in my oppinion, I hate texturing (infact I’ve never done it propperly at all), and I’m sure there are other’s that don’t like modeling, or rigging. If the brief involves every process then you’ll please most of the people most of the time.
Making something like sceenery sounds interesting, not everyone will get the chance to make the next Lara Croft or Nissan Skyline. Often the un-noticed things are what makes or breaks a game.
I like the ‘do a bit and pass it on’ concept, although I don’t see how this could be judged, unless you get teams together (see first bit of post) and you set the brief like ‘make a robot’, and then someone concepts it, someone else models it, someone else unwraps it, someone else textures it, someone else rigs it, someone else animates it. That just sounds like a team project to me though.
Going with that last though, you could do team projects, but have a ‘winning team’ and then winners in each process.
^^ Just me rambling ^^