The problem with two year terms is that consultants & lobbyist end up being vastly more experienced in how the system works than the average representative, and therfore any benefit of the system you use to select the representatives is outweighed by advantages of vested intrests.
This is evidenced by the fact that state senates in the us that have greater restrictions on terms have more bills that are just sponsered, but not written by the politician that puts them forward.