I feel I should add that I've already figured out how to do some pretty cool things just with a) the ability to make new packages classified as makeup, put pointers to existing EA LRLE textures that aren't makeup in them, and give them sliders, and b) the ability to have opacity sliders on anything classified as makeup. And that's just from me screwing around for a few hours and not even trying to make anything I actually planned to use, just proofs of concept. I'm already excited about what other creators will figure out how to do with just the capabilities we already have -- and I can hardly begin to imagine what kind of amazing and creative stuff people will do if we get the ability to add all four kinds of sliders to custom textures.
I'm also concerned about the possibility that some type of content that is added to the game more often than eye colors and skintones will be converted to LRLE before we're able to work with those textures. There haven't been any new eyes for a while, and the new skintones have a second texture in a format we can access... but if, say, HAIR gets converted to LRLE, and then a new pack comes out, with a dozen brand new hairstyles that *no one can recolor*? That's gonna cause a fuss.