3D graphics are easier from a development perspective, especially since for the high-res sprites they're doing in BlazBlue they actually make 3D models first and then rotoscope them, so the models are already there and animated. Why bother with all that extra time and energy?
You're also assuming that the system is going to undergo major changes. Nothing like that is confirmed, or even mentioned. Maybe losing FRCs and Slashback, maybe, but that's all we have so far.
Furthermore, the reason this information was pulled was because of bullshit like this. You guys are flying off the handle based on, what, second-hand information from two sources that were drinking at the time. Sit down, play Accent Core, and just fucking wait.