Pretty much everything you said, Winky.

We really do think on the same wavelength!
I really don't want Lassiter and Shawn to get together on-screen. It's much better watching for the small moments of gropiness and subtle glances than actually *seeing* them get together. In fact, I really don't want anyone to get together. The tension on this show is perfect as it is, and I fear for when that gets disrupted. I know it will at some point and I'm reasonably confident that Steve and the crew can handle it well, but I'm quite content with the way things are now.
I actually like Abigail a lot, and I think it'll be pretty adorable if she and Shawn end up together for a while. I like the idea of Lassiter dating, because goodness that poor man's earned it! After a 4+ year divorce, he just needs somebody who'll care about him! However, if they get a Lucinda-type character, know ahead of time that I will most certainly hate her!
I think my real objection is to any of the four main characters dating each other (again, my objection is only in relation to an on-screen relationship for one or two of those pairings.

). It would just feel wrong!
Like Winky, I would love to see a return to the central point of the show for an episode or two. Not any sort of real back-tracking, but just a revisiting with the issue to see where it currently stands. I happen to think they've all adopted a bit of a "don't ask, don't tell" sort of policy (except for maybe Jules-she may still actually believe him), and it'd be interesting to see how they all would react to someone questioning it out-loud in such a way that it has to be addressed.
I feel like Lassiter's started visibly mellowing out a bit more recently and I think that particular arc should culminate in Chief Vick allowing him an undercover assignment again. It's been made clear that he did at one point do undercover work, but he is now not nearly subtle enough. As Vick said, "You're never more obvious than when you're undercover." Since he's mellowing out, I think he could pull it off again. The divorce is over, I feel like he can probably begin to unwind from that and let go, and then he could be ready. If he ever goes undercover, I will be thrilled!
Seeing Lassiter as the central hero in an episode would be wonderful. I think some people have forgotten that there is a real reason he became Head Detective as young as he did. He's more than competent in his role within the department and I want to see that shown on-screen a little more. All three of the more Lassiter-centered episodes so far have been focused on Shawn needing to help him. I certainly do enjoy anytime he willingly asks Shawn for help, especially when he's looks so adorably uncomfortable with it, but I want a Lassie-centric episode in which he's not shown up by Shawn.
In 65 Million Years Off we learn that he had a hot streak for a while and solved quite a few cases in quick succession and Shawn was not needed. I'd like to see him in that vein, not just hear about it as a sidenote later. Shawn can be around, but in the end I want Lassiter to get to save the day for once.
BadAssCop!Lassie is my favorite. I feel like he hasn't had enough of that to play lately. I mean yeah, he's pulled his gun, and looked damn sexy doing it, but it's just not as...I don't even know what word I'm looking for. I wish I were French-they have a better vocabulary for describing indescribable things.
As for the rollercoaster discussion, Tim could take me on any ride he wanted, whenever he wanted! I'd be more than willing!
I used to love rollercoasters,
especially the ones where your feet are dangling, but I just have a harder time riding any of them now for various reasons. If they're spread apart enough I can do several in a day and feel just fine and still be able to have fun, but otherwise forget it! I have absolutely no problem with ferris wheels, though. Getting to the top and then going down and having nothing but the view in front of you is my favorite part!