I'm not too big a fan of Riker or Troi, so I'm not sold on the Titan plan.
Certainly, using characters from the previous shows might be cool. We'd see new sides of some familiar characters (ten or so years older, more experienced and senior) and how they relate with people new to them, and probably about half the cast new to us.
I'd definitely want Ezri included in that. The EMH from Voyager (possibly a different EMH).