The Soma games were DEFINITELY awesome, but I'm inclined to think we've seen the last of him. The Lords of Shadow game is classified as a series reboot, which when you think about it, they really needed. The Castlevania timeline is kind of a mess, and they'd reached sort of a dead end with Soma. Obviously they could've done more with him, but video game series can jump the shark too.
"Lords of Shadow" was actually the working title that game, in order to keep that they were making a new Castlevania game a secret, as not to take away from their release at the time, Castlevania Judgement. All our beloved Belmonts are so important to us though, that I can see them appearing in the new Castlevania series in one form or another.