Well, what were you originally thinking you wanted the tone system to be like?
I suppose mostly level tones based on a high-low contrast similar to what you see in the Bantu languages (among many others). The kind of tonal systems seen in East Asian languages seem kind of ill-suited for polysynthetic languages.
Your thread on polysynthesis and some comments I have gotten elsewhere have inspired me to rethink the path I have been taking with Terpish, though. I am thinking of going back to the beginning, developing the proto-language and deriving Terpish from that. Working that way would probably help with making more naturalistic tone systems. I am also reconsidering my rejection of case-marking and planning to look at other models of polysynthesis besides the Algonquian one that Vohp taught me.
In the mean time, I am thinking of reviving my long-dormant Socialese project and incorporating some stuff that I like but will probably cut from Terpish to make way for these reforms.
I've been reading the ZBB since 2004, and I noticed that you were stuck on Terpish even then. A similar thing happened to me; I was working on my "main conlang", and I wanted it to be perfect, so I was constantly second- and third- guessing every decision I made.
After a year, I got fed up with not making any progress and worked out the languages of cultures I didn't care as strongly about. It was amazing how quickly I cranked out two pretty different languages. I also got to use some of the features I was considering for the main language --scratched the itch, so to speak-- and I found that I didn't want to use those features again for the main conlang. I didn't feel as much anxiety about the main conlang, either. If it turned out to be a little pedestrian, or a little too similar to the Indo-Aryan languages that inspired it, no matter, because I had a couple of slightly stranger languages to point to.
You might like to know that you sort of inspired the first conlang I described above. I remember that earlier versions of Terpish had clicks, and reading about it inspired me to research click systems and create a language that had them. I liked it so much that I raised the prestige of its speakers, and now clicks are found all over that part of Kreya.
You mentioned taking a look at Socialiese again. It might be a good idea, but again, if it's a language you want to be perfect, you'll probably get stuck on it, too. Starting from Proto-Terpish is a good idea, too, but only if you feel enough detachment from PT to make quick decisions and then let Terpish evolve naturally. Is there a remote part of your con-universe you could spend a little time fleshing out? Have you considered trying a futuristic version of an existing language? What does Lakota look like a few centuries hence?