I don't know about the shield generator (how it would affect gameplay? Too defensive?), but I think the trap is a MUST!

It would halt / delay other players movement, a mechanic already in the game for many items. (Would be interesting to use against Scouts and über!)

Also, it fits so well on the place of the teleporter, and it might help teamwork on situations where you don't use much the teleporter (CPs and respawn changing).

+1