It's hard to believe it's almost 2016 and MAME has not emulated Sega model games like Star Wars Arcade. Id love to have it running in my arcade cabinent to welcome The Force Awakens. Heck I would pay for a legit copy if it were released anywhere else (the only home port on the 32x is not up to par).
I dont understand why progress has been stalled, there are some great games that cannot be played anywhere else. This should be reason enough to overcome any technical challenges.
because they're difficult?
there was progress on model 3 earlier in the year, all the protection / decryption was figured out.
popularity of games has nothing to do with when they get emulated, nor how easy / difficult they are to emulate.
model 1 happens to be especially difficult because per-game math related (including important gameplay calculations - physics and the like) are done by a chip for which we don't have the code.
model 2 has a perfectly good emulator available (I even have the source code) but some of what is needed to emulate it (being able to stall CPUs until data is ready etc.) doesn't work well in the MAME architecture, it's much easier to just cheat with a standalone emulator to make things work. Also Model 2 again is 4 different platforms, with the early ones again having code locked away in chips. The existing Model 2 emulator also doesn't bother to emulate some of the CPUs but just HLEs them, emulating them properly in MAME will be slow.
they'll happen when they happen, can't give you a time frame, could be next year, could be 10 years from now, could be never if the project loses momentum before it happens.