I think it all depends on the game, there are some that use the vibrate function on phones and tablets so I don't see why they couldn't port that over the rumble packs.

I think the main reason it was left out of the OUYA controller design is it would hinder customization. The controller and case for OUYA were meant to be easy to customize, I don't know if you ever took a controller apart but one of hardest things to not break or fit into a customization is the dam rumblers.