Ideally, as I print photos mainly, I get more then 4 colors and decent color management.
Added bonus for scanning (with or without document feeder).
Not much else there. Pay-per-page subscriptions are ok, by the way, price wise for home office use.
Then it comes down to innovation in the fields of color management, ink mixing and print heads and paper handling. And inks, of course.
Anything else is just pointless, and nothing I would call innovation.