didn't get any follow up yet from your team on this subject.
I was thinking of another alternative, if you can provide one easily:
Allow a new method to compile a new image based on a display group or using some canvas-like solution and either allow to save it to disk or allow to use it as a regular image.
Using this, I can dynamically create a few large images from the non interactive layers, and load only them to the map instead of the thousands of tiles that were used to create them. This will reduce the tile count significantly on expanse of the texture memory used and load time. I've tested it manually and it shows better performance than current solution can provide on single core devices. Problem is, I can't do it on runtime.