With mid-range products like the SX700, Yamaha is more likely to add a feature and issue it as part of a new model, e.g., SX710, if such a thing exists.
There is no real profit motive to implement and issue a feature upgrade to a low- or mid-range product. I don't think we've ever seen a "marketing emergency" where Yamaha are losing gobs of sales to a competing product because of some specific feature.
Yamaha just doesn't roll that way. Updates for low- and mid-range products usually fix bugs. The situation for Genos shifted because customers have bigger expectations for expensive, premium-level products -- and are willing to pay for it. Until Genos, Yamaha didn't offer feature updates to Tyros either. Yamaha changed its ways when its competitors offered more extensive updates.
-- pj