There's a huge issue here, and that is that any image app that relies on Apple's Core Image is working within a very set bunch of parameters, both good and bad. They get to utilize system hooks and not write reams of extra code which keeps things neat and brisk. OTOH you can never, without doing programming that I've never seen in all of these Core Image based editors (and there is a handful) do things which are much different from what anyone else is doing. It all becomes about the interface and not much can be done about these features that people are asking for as long as it relies on CI. I'm not a programmer and don't know the nuts and bolts of what's under their hood, but people have been asking for the same features (some 16 bit support, less limits on layers, layer styles) for literally years. I don't see them as being in the cards given how the program relies so much on the system architecture Apple provides.
This is why Adobe can make products that go beyond what all these Core Image based programs offer (again, not that I'm faulting them in the least, but they are what they are), and also why people who desire these features are not going to find them in a CI editor, and why they won't ever quite be competition for Adobe products for those people. Different niche.