It's Capcom, so I'd say there's a pretty good chance we'll see a DMC5 in the next 2 years. I mean they're still pumping out Resident Evil and Dead Rising sequels, and DMC is still one of their biggest series.
My guess is they are going to use the HD collection as a gauge for how popular the series still is. I'm almost positive the next one will be DMC5 and not DmC2, because the reboot was not very well received. It's not a bad game but most people didn't like them changing Dante from a smartass anti-hero to a whiny emo, especially when DMC4 pulled a Metal Gear Solid 2 and you played most of the game as the Dante-clone Nero. Plus that game didn't seem to be any kind of closure to the original storyline.
I'd be ok if they decided to keep both series but treat them seperately, like Call of Duty used to do when Infinity Ward and Treyarch would alternate COD games. But my guess is the reboot will be quietly ignored.