Voice-of-Shadow I see, you meant Warp Deformer. We have no plans to implement something exactly like that, but the ability to use linked meshes in a different slot, which we are already considering adding in 4.3, could be used to achieve a similar effect: EsotericSoftware/spine-editor195
We have received many requests for masks, but we do not plan to make such major changes in the short term. In particular, we plan to make improvements in 4.3 that will not have much impact on runtime, and allowing inverting via masks and allowing the use of alpha masks will have a significant impact on runtime, so I doubt they will be added in 4.3. For past answers about masks, you may find the following thread helpful:
https://esotericsoftware.com/forum/d/26148-request-inverted-clipping-masks
https://esotericsoftware.com/forum/d/26987-image-mask-or-alpha-mask-feature
Markers are one of the features we have been wanting to add for a long time, and in fact there is an issue that we created quite some time ago:
EsotericSoftware/spine-editor531
Many of the other ideas already have issue tickets, so we hope you will take a moment to review our roadmap:
https://esotericsoftware.com/spine-roadmap