I honestly think that it will partly be like that with lots of panels sliding over each other and compressing...but coupled with the basic shift and move parts of the "norm" transformation. Sorta of a compromise of the two.
As for speed I'm betting the first couple times will be slower, particularly with Prime's first transformation (which will probably be close to his TFTM slower transformation). Then after that, it will be fast. I would also imagine Starscream's transformations always being super-fast and energetic.