Thanks for sharing your suggestions! FWIW, you can see what we have planned here:
https://waffle.io/EsotericSoftware/spine
1&2) We are finishing up version 3.7 (audio and other things), then version 3.8 will have a curve editor.
3) Separate keying for x/y is planned. You can subscribe to the issue on GitHub and get an email when there is progress.
4) Scaling to flip isn't really a trick. I'm not sure it would be improved with an explicit flip.
5) Note that Spine saves backups periodically and when you save. It uses a numbering system to organize the backup files, but it sounds like you want to save a copy with a meaningful name. Save As
does what you want, I think? Maybe you are asking for Save Copy
? That would do the same as Save As
, except it wouldn't change to the newly saved project.
6) There are many benefits to knowing the hierarchy. It allows for assumptions/optimizations and some hierarchies are not valid for some features. Allowing the hierarchy to change increases the complexity of a number of things, which is why we chose not to allow it. You can simulate multiple reparenting with multiple transform constraints.