I think I can understand why a 'straight-ahead' player might want these voicings, but you DO have to give up the ability to play any chord in any inversion you want and still get the correct chord.

You asked why I would ever play a 3rd inversion Asus? How about this........... Play (in the key of E) the chords of E, A, Asus, and A , a common enough change (perhaps not jazz enough for you, but prevalent in pop!). The way I would finger it would be EG#B - EAC# - EAD - EAC#. This removes the need for a change of hand position and is the correct way (or one of them!) to get voice leading for those particular chords.

Rootless chord recognition forces you to play certain chords in certain inversions - kind of tyrannical behavior not often endorsed by jazz players! I prefer to not have to remember 'don't play 3rd inversion sus chords, the machine will play something else entirely'.

The only way I see for this to work would be for a preference so you could turn it off when you don't need it.

Anyway, to answer your first question - No, the G70 doesn't do rootless voicings. On the other hand, it's piano sound (The Grand X) is the warmest, most detailed and playable piano sound of ANY arranger (and workstations, too!), and incredibly low latency - you get a real feeling of being 'connected' to the sound. You have to go to a GigaSampler rig to find anything that sounds better (if you can afford the cost of a system that's low latency enough to play it 'live'). So what's more important - rootless voicing recognition, or a piano sound that makes you feel you are playing one (action aside)?