I feel obligated to nuance this, GroovyMAME is pretty much the embodiment of many things the people asked for, and they were legit right to.
Which
people? A dozen of enthusiasts who kept their CRTs? That's never a wide userbase. Nor it actually is the several hundreds it got today who aren't asking for much as the main job was done when they came. You're just an exception.
If you go as - best example being - in MAME's shoes and look down on the user base for long
I've seen so many silly petitions coupled with uncivil tones that I kind of find easy to sympathize with MAME devs. We indeed weren't so lucky that these talented devs actually liked video games much (and the ones who did a bit quickly moved away?), but... we indeed were so lucky that these talented people without much interest in the games themselves dedicated so much effort and time to the cause. I actually believe that both conditions (loving the games and loving game disintegration) have to be mutually exclusive.
**: This means people will put FPGA and real console side by side and look if timing is correct and if there are graphical/sound glitches.
And they're found out (by the few that do this) and not much is done so many times? I don't know, check the Neo Geo core status, or how the Cave games are being added. Check how they got the most capable man in regards to arcade games accuracy dedicating his efforts to the Neo Geo Pocket (a handheld which owes basically all its merits to its particular D-pad, so has little point on Mister). We're clearly in a phase now of getting there in as much as possible, not as well as possible, and that's concurrent with the project's popularity. Yeah, I guess there's a higher level of exigency today and devs listen more (thanks to patronization, let's not fool ourselves), but it's far from optimal.
THUNDER FORCE II - I have Megadrive version
It's a downgrade. It's a bit better balanced (easier, shorter), but it has less stages and simplfied visuals and sound.
GENOCIDE - I played PC Engine CD version and I don't like this game too much
You won't be missing much, then. It's likely the worst entry in the list.
GENOCIDE 2 - the same situation but I played SNES version, maybe I didn't play to long, is it good ?
It's definitely much better (than both, the SFC version and the predecessor), but not a must.
ZAVAS - not interested (these days I don't play jRPG too much, especially when are in japanese laguage only)
EMERALD DRAGON - japan only RPG so I wasn't interested, PC Engine version exists
Glodia's games never are your usual JRPG and combats are really strategic there. The PCE version of ED (like the SFC one) is totally different. But yep, Japanese only for now, I'm afraid.
KNIGHT ARMS - I've seen this long time ago but I don't remember how good it was
It's ultimately an average/decent game but its historical context is something else. It's Thunder Force's creator first action game right after leaving Techno Soft and forming up his own company, so he tried to awe everybody with a unique approach which seemlessly concatenate Space Harrier-like phases (with full faux 360º rotation) with side-scrolling ones. It also has compatibility with analog controllers.
WANDERERS FROM YS - so many version I've seen, any better than SNES/Megadrive? In english ?
Never played those, but it gotta be as at least the MD version is based on the X68 version and the SFC one had a subpar developer. It's a remake (of the 88SR original) by Falcom themselves, and their only X68 game at that. Only in Japanese and it's protected, though. If you want an English-language console port, the PCE is the one to pick as the music there has no equal.
LAGOON - almost the same as SNES version
As much as SFC Street Fighter II is to the arcade game.
GENJUUKI (Undead line) - I have mixed feeling about X68000 port, for years I played Megadrive version, is it better ?
Sure thing. They're very different -- you'll find Genjuuki to be a glorified remake with lots of new stuff of the splendid MSX2 original while the MD version is a very compromised take in every regard 'cept for the bosses.
ARCUS ODYSSEY - I never played X68000 version but it's (at least visually) almost identical to Megadrive version
It's one of the closest X68-MD ports by Wolf Team, but like the others (Granada, Axis, which I forgot to add, and Sol-Feace) it has more content and better visuals/music as well. Granada, I actually prefer the MD port, though.
DIE BAHNWELT - I din't see this one, top down shooter, might be interesting but it's hires mode
It's
Alien Syndrome meets Ys, kind of. A quite special one. Hi-res, but what's the matter.
YS - remake and in hires mode :/
A good remake indeed, despite all the camp it throws at you. Easier than the original, but it got awesome levels of care by the authors -- unique NPC throughout all the quest, improved save system so that no disk change nor keyboard is necessary, much better collision detection thanks to the higher resolution. Falcom's own remake exists and is better, but overlooking this is a mistake.
LAST BATTALION - the same problem as with Daioh/Shienryu games - an updated (!?!?!) port of Override from PC Engine
A deep revision of Override, indeed. It's a Sting game, and these people never made a turd.
AKUMAJOU DRACULA - since I have Castlevania Chronicles on PS1 I didn't bother to test it. Original version is on CD
The port in Chronicles has some issues which make of it the poorman edition (and I'm saying this being it the one I own as well, even if it's still sealed). The only problem/disadvantage with the X68 original was the lack of a 15-kHz mode, but that's automatically solved with MAME.
SCORPIUS - it's on my list to play
PHALANX - I have original X68000 version and indeed X68000 version is better
OLTEUS II - on my list
AQUALES - on my list
ÉTOILE PRINCESSE - on my list
So that's not enough to "justify emulation" or what's your list for?
As for PC-8801 - I was never interested it's library just like many other japanese only computers. So many computers and games :/
Your lose, then, I guess.
Proabably You have right, someday I'll probably get to this system games.
Just remember not to mistake the PC-8801 with the PC-8801 Mk-II SR. It's much like the MSX and the MSX 2 case -- entirely different things despite the retrocompatibility (and the people's claims). The 88SR is where the good stuff resides.
I don't remember any stuttering. Maybe the speed up/slow down games to match GameCube refresh rate.
Apparently, only stutter. The Swiss hack halved it somehow, but still there, they say.