We looked into supporting our own official Construct plugin back in 2017. First we considered supporting C2, which would have been possible with their JavaScript SDK, but we decided it makes more sense to support the latest technology, C3. At that time C3 was too new and did not have the necessary APIs (the SDK had no graphics rendering yet!), so we tabled making a Construct runtime.
It's interesting you prefer C2 even after all this time. That's not really encouraging, as I'd expect that the significant effort being put into new development (C3) over 6+ years would be strictly better by now. Integrating with an older game toolkit isn't great as we can run into bugs or other problems and if development of the game toolkit is no longer active, it could compromise our efforts. If we did make a runtime, it'd probably be for C3.
Unfortunately we don't currently have plans to support our own Construct plugin. We have a lot of work still left to bring physics to all the runtimes for 4.2. After that we have other plans and won't be able to get to a Construct plugin any time soon. Sorry I don't have better news!
Other developers with more time available could make a Construct runtime using our generic runtimes. C2 is 100% JavaScript/HTML5, so it can use our generic spine-ts runtime, which does most of the work except for rendering.
