Vita is too underpowered, sorry.
Skullgirls on Vita was a year late because the port was a nightmare, and we had to switch it to 2D backgrounds to get it to maintain a steady framerate.
The main issue is that while on paper the Vita looks very similar to the PS3, with separate main RAM and VRAM, the bus connecting them is incredibly slow on the Vita. And Skullgirls on the PS3 is all about rapidly shuffling tons of animation data between the two. Like, mimicking the PS3 memory setup on Vita got us ~20 FPS instead of 60 on the PS3.
So we had to reduce the size of the sprites significantly so they could all fit into the VRAM.
Indivisible has about the same amount of character animation data in memory at any given time, and the environments are much more complicated and can't be made 2D.