You've assembled a system that looks like it ought to be quite good. Unfortunately, I haven't heard any of it. I think you've gotten a good bit of thoughtful advice here.
If you could articulate what it is you might like to achieve, that would be helpful, even if you just want something different. We've all been there, and unfortunately most of us have made changes to already decent systems that have been misguided moves.
If you just want something different, I think it is safe to say that changing from your Tannoys to Tektons will accomplish that. I haven't heard the Moabs, but I have heard other Tektons, and I will tell you that I was impressed by their bang for the buck. If the Tektons I've heard are any indication, they are an outstanding value proposition. You might do well to have a chat with Eric at Tekton. I'm told Eric is a straight shooter. Nothing to loose but a little time.
I also think @audiokinesis advice is worth considering. Since you already have a Debra system installed, I'm going to guess that you have the problematic low frequency range figured out, and I would further guess that you have a decent understanding of room acoustics. If your current staging and imaging is an area that could be improved, that could be a productive move. Perhaps you might want to also consider going with monitors rather than full range, since you have a DEBRA. That opens up a lot of possibilities for placement that you usually don't have with full range speakers. If you are in a dedicated room, monitors can open up the near field listening option, which as you know, can be a simpler problem when it comes to installing supporting room treatments. Again, if you are just looking for something different, that might well get you there.
I can also tell you that I moved away from SET and went the OTL route. I understand and appreciate what a great SET amp can do, but I'm as much in love with my Atma-Sphere M-60's (with the right tube complement and pre-amp) as Millercarbon is with his Moabs. They've made me stop looking and stop wondering about amplification. Any system I build in the future will start with M-60's.
It could also be that you are not really looking for something different, but wanting something significantly better. You've have had a couple of people mention room treatments, and since you didn't mention that in your system description, it may well be that would be a good move for you. Your Debra should have the low frequencies in good shape, perhaps leaving some opportunities for improvements by addressing early reflections and balancing direct vs reflected sound.
Good luck!
