[GMKlenklen]

Nice ideas! Personally I'm in love with the holonomic (4-wheel kiwi) drive train for maneuverability and cost... However the diagonally mounted omni/traction wheel is an excellent idea in my opinion (if you don't want to move sideways)! I just think that maneuverability is increased dramatically when you ad another degree of freedom!

Now, for the complaint about holonomics not being able to go up ramps, I think you have a good point in that it's relatively hard, but definitely essayer to maneuver once on the ramp! I believe I can speak about this as the driver of a 4-wheel drive all-sky wheel drive train in the '06 competition. Once I got on the ramp (really easy) I could hardly move along it, it was something to do with the insane difference between driving on a level ground, and having one wheel atop the ramp providing bookoo friction against a turn... Now for a kiwi drive friction may be the deciding factor regarding your movement at all on said metal ramp, but you could definitely provide force in any direction you choose!

But for overall simplicity of design, and a good two degree of freedom drive train ideal for getting around your opponents... I'd pick the diagonally mounted omni/traction, because your not a rookie team, and you can probably handle it!