Your right bob about mass and speed. That would play out in two ways as i understand it: one would be the tendancy of the structure (the craft itself) to dishape as it turned, creating stress and possible airframe failure. Some shapes and designs resist this more than others ( sharp angles are terrible at handling these forces) the second would be increased need for energy as it turned... Lots of others im sure...
As for my neigh sayer friends: :P
Remote control tv's wernt invented by people who said it cant be done. Every awesome piece of technology starts as somebody's "why not?" moment ;) 10 years ago plasma shields were bullshit science fiction. Today they are small scale reality :)