Phantasy Star's not going to benefit from 3D in terms of play experience the way the Super Scalar games have. :|
so you can clearly see the seams where they were encouraging you to shovel in coins
Not that you could even do that with the SDX cabinet, which was supervised and probably queued a prodigious line of consumers after your one play. Playing on an upright cab, though (or, in our case, the 3DS), it's perfectly playable as a 1CC game, though it takes a long-ass time to master the game (my usual playthrough style involves playing as well as I can from start to finish, which probably isn't healthy, but certainly means I don't get to fudge). GFII, excepting its two flaws (visually obnoxious lava and random spawn patterns for some shootable things), is really amazing stuff.
X and Y board seem to be the best they can do, and these boards mainly produced in your face racing / shooting games. What they may do is adapt another Megadrive game into 3D like they like to do. Gotta make that Gigadrive work.
They have no choice but to port Mega Drive games, since they're less work and more profit than the arcade projects. I still want to see 1981's Turbo, though, as that's perhaps SEGA's first arcade powerhouse still worth playing.
Return of Death Adder would definitely be interesting... though I hope that they just skip to that and ditch the rest of the series, frankly.
God forbid they go with Golden Axe 2, then 3, then Death Adder!
As far as future racing games go, I'm still most interested in Turbo Outrun. Something about the turning animation for cars in Outrunners and Power Drift really turns me off of them... though I can't say I've actually played any of these, so I hardly know what I'm talking about.
Power Drift needs reappraisal with a top-notch M2 port (the Yu Suzuki Game Works port is flawed!), but Turbo Outrun and, if at all possible, Outrunners would be just as great.