at a guess...
I reckon a virus with more knobs or control features on to replace the ti/2. The ti v2 looks too similar to the original to account for the price hike. I paid £1200 new for my original TI KB , now that it's near £2000 for the Ti2 I can see access trying to make it look like a much better or upgraded synth.
Also a new OS , maybe even a better version of virus control software. I reckon compression/gating/ducking being added to be more in line with the glitch type music which is being produced at the moment.
(I was spot on 100% right when guessing in the NAMM thread just before the Ti/2 showed up
)