I hope for simple video option in VST fromat, rewire, whatever. Arkaos has rewire but I dont really care for its FX, who wants to see the infamous kaleidoscope or bloody tunnel, and the GUI is still in the past century.. If I had option of having straight video playback track(s)in Live, no cheesy or whatever FX just possibility to midi control, I wouldn't bother about any VJ software.
I simply dont believe in all in one solution, but more modular system, meaning Live just playing the the video while the FX can be done by hardware or software module.
Separating the FX and video playback makes things simpler and safer for live performance.
If Ableton wont bring such option, I believe if reasonably priced you might earn some money with such VST. As far as I know the VJ scene, everybody,already using- like Cold Cut or knowing it from others, loves Live, since its concept really fits the VJing ideas and workflow. Apart from people who are already doing visuals, there must be hundreds of Live users who are interested, thought about or would like to check it out.
The VJ software is far away from audio world, actually half amateurish, in the sense that the creators are mostly doing it for themselves and due to limited niche market nobody can really make much money with it. So most of the software remains half baked and most unfortunately half reliable. I dont think it will change, until AV becomes more mainstream, popular. On other side the prices of quality software have to be rather steep like VJamm for example.
So if I was you I would go for modular concept, VST video player , Video VST FX modules with various FX sets, DMX module etc so you could leave to the user to go for what they need, leaving flexible upgrade options. If there is really money in it I am not sure, the fact that Korg wound up their video line speaks for itself. When you see that you can get decent complete ( though simple) Vj software for as little as 59 $- http://www.neuromixer.com/
or standard software like resolume for 200 and Arkaos for bit more then there is not that much to make. The idea of inexpensive modules might work better., side effect, if your software is cheap enough nobody will bother to crack it.