Obviously this is a joke thread, but I think the kind of pick up and play gameplay that works on phones is a really good space for bringing back some of SEGAs classics that probably wouldn't sell anywhere else.
I think Fantasy Zone would be a great example, and you wouldn't have to even change much of the game at all as it lends itself perfectly to the whole free2play thing. I would be so down for a new 2D, side scrolling cute-em-up Fantasy Zone which plays exactly like the classics. Give it a good number of levels and bosses, perhaps a light story like the old games had, something to show progression. Just as in the past use the in game money which enemies drop to buy new weapons and add-ons from the shop only this time have the OPTION to use actual money too.