Agreed about both Lithgow and Hall. Trinity was a great character. I cracked up every time he randomly called people a kangaroo.

I really don't think Deb will be the first person to find out the truth - I think she'll be the first one to suspect things but ultimately won't admit it. Here's my prediction. Quinn and Deb start dating. Deb starts snooping more and more. She eventually gathers a ton of circumstantial evidence that suggests Dexter as the Bay Harbor Butcher. Quinn finds this litany of information and it validates his suspicions about Dexter. He goes rogue and goes after Dexter kind of like Doakes, causing Deb to break up with him. Dexter kills Quinn, Deb somehow finds out, turns in Dexter, and beats herself up over it.
that would be awesome. I could definitely see a Quinn-Dexter feud on the horizon. They butted heads a time or two in this past season. Dex caught him stealing cash at a crime scene. Quinn followed Dex one night into the bar.
I think they could end next season with Dex killing Quinn and Deb finding out and then having season 6 being the last season.
Trinity was a bad ass. I think he also dropped a few "You Stupid nag!" lines.
Dexter was really starting to crack. Rita caught him busting the light near their house. He also got arrested over stupid crap. He nearly got caught at Trinity's house before the FBI came in. The thing that happened at the end could really push him over the edge next season. He is not following Harry's code to a tee like he used to.