I was late to the party with Dexter (crammed 6 seasons into the past 4 weeks... don't worry I do have a life) so knew about Rita and was hinted that Deb would be incorporated into Season Six's last episode.
So! I hope Season 7 and Season 8 have good cliffhangers so I can be surprised instead of knowing what is going to happen.
I think for the next couple of seasons Deb accepts Dexter with what he does. I think that will make him feel better about his dark passenger etc. if he has some acceptance.
Lagueirrta (or however you spell it) is a bitch and I hope she gets her come-uppance.
Battista and Quinn -I hope they find happiness
Masuka can just remain as funny as he is.
Louis - interested to see what they do with Louis.