I doubt (and hope!) that very little from the FantomG will make it to any mythical G80 arranger...
Virtually NOTHING from the FantomX made it to the G70 other than the underlying engine (very fast response and 128 voices and a slight change in effects architecture) and some of the basic samples, including the superb Ultimate Grand, renamed GrandX.
You have to understand that for all but the PA series, these arrangers are NOT based around their WS counterparts. There is next to nothing from the MotifES line in the Tyros2 other than samples, either... And, in all fairness, very little from the Oasys (other than engine and a few samples) and M3 in the PA2XPro. It is still based squarely around the Triton's architecture.
The thing I think most Roland users are looking forward to is a RETURN to some tried and tested behaviors from the very successful G1000, along with the best in it's current OS, such as the Cover Tools, Makeup Tools and new OTS implementation.
What are the touted features of the FantomG? An 8-track audio DAW, and some very intricate modeling of the Rhodes (and little else)... It's not exactly on my front burner of features to have! The sampler section is still (like ALL hardware samplers) too slow for practical arranger use. Possibly some of the loop-slice features might make it to the arranger division, but somehow I doubt it. Despite Ian's contention that the Yamaha's are the 'real' home keyboards, Roland's OS and feature set is FAR more geared for those that DON'T need to be encumbered by samplers, loop-slicers, and a plethora of 'pro' features that few home users will use.
This of course is absurd, as they actually BUILD them for the 'pros', but leave out all the juicy stuff Yamaha waste on their 'home users'
I'm sorry, but the FantomG is NOT sexy, at least in my eyes... It's your mother, dressed up in your teenage daughter's clothes!