"I hope this feature won't be difficult to implement" ... goes on to describe the complex ways the feature should work! :haha:
We have a long list of things that would be amazing to have in Spine. We regularly do big features, but we also try to pick the features that are easiest to do but still have a big impact, because that way we can get more useful features to you. Sometimes we have to cut down a feature to its simplest form so we can get it in, but we can add to it later.
This feature may make it into 4.1, where we are focusing on such quality of life type of improvements, but it's still early and I can't be sure yet.