I tried an earlier version of a tox client. At that time, there were at least two competing clients that looked the same and did the same things. Is the tox civil war over yet?
The Tox protocol is really the core tool. As long as the protocol is well-defined and maintained, I think developers should be free to make whichever clients that they want.
I used tox ages ago, and I used the Blight client or whatever it was called, and I liked it pretty well.
I think a bigger issue is convincing people to use it in small groups. My whole team is just fine using Mattermost/Hipchat/IRC and the majority of them don't see the need for something like this.