I do like what they've done making the first 2 human attacks available to dwarf/nova respectively. It would ease up the slot shortage if there was more power sharing like that, except of course PBs and WSs have quite a different human form loadout making that difficult to do in practice, e.g. human PBs have Solar Flare, which could carry into dwarf form and replace White Dwarf Flare, except you wouldn't be able to do the same on WS, and that aside you'd have to wait until lvl 26 to get it and be forced to spend a power pick on it even if you only ever intended to use it in dwarf form - so complications abound! I'm sure some people would be upset to lose Reform Essence and White Dwarf Sublimation as separately usable heals as well.
The logistics of trying to do it in a reasonable way across PBs and WSs, and without breaking existing characters, mean it'd probably be far easier to simply create a new Kheldian (or Kheldian-like) AT from the ground up using some of the fancy new tech that has been added since.