Its not just cd based systems that need love its others such as the wonderswan (Has some pretty good rpgs like an arc the lad game and the choaniki (Yes that choaniki) card rpg) and the various sega systems.
Lets not forget pc engine. No ones tried translating the far east of eden games as far as I know and those look amazing!
Not to be nitpicky, but the PC-Engine IS a cd-based system. Well, it had the hucards too, but I doubt there`s any hucard-based game that anyone really cares to see translated. Pretty much all the RPGs are on CD. Now, I agree with the sentiment though. I don't believe the Snes is out of translation-worthy games-there`s a good, oh, 15 I'd love to see-but it'd be awesome to see the PC Engine and Sega Genesis get some love. If, say, AnEarth Fantasy Story was a Snes game, you know it would've been translated years ago. It's basically the precursor to the Tales series. I have a fondness for the Startling Odyssey series, myself-I'd especially love to have Miraculum in English. Of course, that`s a PC-FX game, so...
That said, each individual romhacker will work on whatever game is fun for them to work on. It's a hobby, so there's really no room for complaints.