My reference was pure Dimension Pro, and took a look yesterday at Rapture LE which came with Sonar.
I don't see much that is improved regarding making new interesting timbres(even looking at the obvious that you can work on envelopes, which are grayed in LE).
Basically a browser improvement, which is not bad idea, but maybe not worth all the effort.
NI and Arturia have this from long ago.
I would have liked to see improvements on:
a) multiple outs
b) sound engine stuff like oversampling when rendering or always
c) modulation extensions like Waves Element has - with 4 lfo's and each can take input from about 20 sources, and roughly a dozen targets. DP and RP has lfo on each envelope which is nice, but v2 should maybe extend these things to be able and create really new sounds.
d) use of VST3 features like audio inputs - that can serve as an Element from other synths.
Maybe a short record scenario even, if continuous audio stream is difficult to handle, that you can record a snippet and is mapped as an element and waveform.
One of the above, and I would look further if to buy.
Otherwise, it seems that Mac people are worst case regarding installer issues. From KVR some seems to gotten entire folders wiped out with presets they had from other synths - installing RP.