Most of the lack of innovation in printers (and scanners) comes from the problem that, once you've bought their hardware, there is no incentive to make the software that ships-by-default with it great. The innovation isn't the hardware, the innovation is waiting, stuck between the hardware and the operating system (e.g. why does my Brother mysteriously screw up my right margins on Windows?) and stuck between the application and the user. The operating-system printing dialogs are way too complicated for mere users and the printer-manufacturer's printing-dialogs are mostly rebranded operating-system printing dialogs. Users just want their bits to burn onto their paper, appropriately and reliably.
You know, it might not be such a bad idea to make a printer-bot ala a RepRap that allowed you to put any writing instrument you wanted into the cross-hairs and slowly draw out your documents like a plotter. The ink might be "cheaper" that way and it would be kind of fun to watch 8 of them on your wall draw your documents concurrently.