"For me, workflow improvements are what I want out of it. For example, Zebra can do additive and wavetables, but it's a bit clumsy compared to doing it in Serum. An improved editor would be nice. Also, as some of the u-he tutorial videos show, there are some workarounds for transferring modulation data to another patch -- but it would be nice to be able to save modulation presets and simply open them in another patch rather than go through the ticky-tacky workarounds."
Odds are, things along those lines have been mentioned already, but thought I'd add it anyway

