Double Dragon. It's been a minute since we got Advance, and I'm not even going to bother dredging up that XBLA "remake" from a year or so ago. Million, I know you're struggling with trying to make Kunio-kun into a profitable commodity, but how about giving us a nice Double Dragon brawler, while you're at it?
Hiryu no Ken (aka Flying Warriors/Flying Dragon). I loved the NES games in the series, which basically were side-scrolling fighter/platformers that mixed some faux RPG aspects into the fray. Culture Brain, however, has seemingly never been the same after the 16-bit era, so who knows when they'll come back? I miss the old school CB...
Gargoyle's Crest. Even a HD remake, or a DS port, of Demon's Crest would suffice for now. But really...Red Arremer (or Firebrand, if you will) NEEDS to have another game. He deserves it.
Rockman DASH/Mega Man Legends. How long will you continue to cocktease us, Inafune, before you FINALLY give us the third game?
Guardian Heroes. Treasure. While I liked the Advance "sequel", and the extra mode in Bleach DS 2 was fun...seriously. Where's a true-to-form follow-up to this Saturn classic?
Sengoku. While being a relatively sub-par beat em up series by SNK/ADK, after Noise got it for Sengoku 3/2001, they made what was probably ONE OF THE BEST BRAWLERS EVER MADE! After the new Power Instinct, it would do my heart right to see another game by Noise. And hell, give the third game a PS2 port, already!
Vampire(Darkstalkers). This FG series needs a new continuance in the WORST way. Capcom, you've got like 3 FG engines at your disposal (SF4, TVC, Fate). ONE of these should be able to host another round of festivities for Morrigan and her lil friends, right?!
EDIT:
Forgot this...
Legacy of Kain/Soul Reaver. The series took some spills and had some set-backs towards the end (most notably, people leaving, and the awesome-ness that was Tony Jay dying), but I still would like to see the series come back in style, one day...