I think that half the difficulty with the transformation is that at one point the torso has to be a bunch of floppy, unsupported panels, and the other half the difficulty is that the figure is just so dang big. A big figure is hard to handle, and adds a layer of challenge even to things that would otherwise be straightforward. A big figure could be designed to be stable and supported at every step of the transformation (the DX9 trailer seems to be pretty close to this), and then its large size wouldn't be an obstacle when transforming. A small figure can afford to have some steps when it's floppy, because you can probably support it with one hand while transforming it with the other. XTB's trailer is so big that even two hands aren't enough to support it at times, and it's floppy on top of that. I haven't been able to transform it without having to just lie it down on the desk or the floor, and I don't find that satisfying at all.