The pi one could do 90 frames/second for high speed photography using the raspberry pi camera module. Can the pi2 get a higher rate with its 3 extra cores + memory ?
I don't think so. As far as I am aware it's the GPU which does all the camera "heavy lifting" and communicates with the camera via the CSI interface.
I'm not sure that the ARM core(s) have any part to play in the image processing so I expect the 90 fps figure would be unchanged.
Of course post-processing may well be improved. The new cores have NEON which can provide a huge increase in performance for some graphical tasks.