Guys, I have tried to ask too. But, it's kind of Brashmonkey is still too busy with Spriter 2.I don't blame them, it's just their schedule is overwhelming, no need to rush them. We should understand.
I would recommend using something else for now though, if you can. Because, we might be looking at something late 2019 for stable Spriter 2, not to mention the plugin runtime has to be rewritten, which may take longer, especially with early release bugs.
Performance-wise, using C3Runtime with frame-by-frame animations could be much more effective than using Spriter in C2Runtime. I tried in my tests and it's not so bad, if you do it right and know the ins and outs. Especially when memory might not be that much of an issue anymore.
My point is, what's the point of cool animations and animation editor if the performance is still of no quality. It's better to just use frame-by-frame animations if it will be faster anyway. Don't pressure Brashmonkey and just adapt for a while. They are already trying their best, as we can see.
It's better to adapt than waiting for a year to make a game or release a game. ;-) You won't even remember you need it.