Hey, I have been learning Spine over the last month or so, and wanted to make a suggestion (if this is the wrong place, let me know and I will delete the post).
When you export something, the automatic texture pack goes a good job, but it's only working in squares which limits the possibilities. Such as in the simple example below, I have two horse shoes, and they take up quite a bit of space.

It would be great if when I was exporting them, it could bring up the automated texture pack, but with everything select-able so it can be moved around and rotated (blue outline to show the default texture coordinates - ideally you could toggle it between the default square and the meshes you have created).

Then you could move, rotate and intersect them, making a far smaller final texture size (in this case, 165k pixels for the original and 129k for the reduced image):

Currently for something simple like this you could just manually make the final texture pack, put it into the project twice and then cut around each horse shoe using the mesh tool. For projects with tons of pieces though, that might not be practical, and could cause a lot of issues if pieces need to be added or changed.