I'm tempted to say Panzer Dragoon (either a shooter or another rpg) but I'm wary that a new entry might be terrible and ruin what is currently a very good little series. Another would be Phantasy Star which technically isn't a dead series, it just is in the west.

Really I'd welcome a new game from most of their franchises though. They own the Technosoft IP too so maybe another Thunder Force.

The really and truly amazing Streets of Rage PC remake - which is completely free, too.

...remakes SOR1-3, adds a lot of stages, characters, features... and plays exactly like the originals. Perhaps the best fan project ever, in my eyes.

One can only dream.

Also, yeah.. Sakura Wars is coming back, check the news

E.S.W.A.T. City Under Seige

Of those listed: Jet Set Radio.I have an affinity for Shinobi as well. Not listed. Herzog Zwei. But I see Sega was only the publisher. Ah well. Herzog Zwei.

Voted for other. Panzer Dragoon.

I mainly want to see Shining Force because I'd love another tactical RPG from a big publisher.

But i'd also like to see Panzer Dragoon and Monkey Ball come back. I haven't played either of them. Monkey Ball looks like it could potentially be one of my favorite games of all time .... if I ever got the chance to play it. Specifically the Gamecube one. Panzer Dragoon looks like a unique property. Although honestly I wouldn't mind if it just came back as a collection of all four games.

Skies of Arcadia, Jet set radio and Panzer dragoon.

I think  streets of rage series is overrated.