On the Creators screen for the 20th ST birthday demo I spent about as much time as getting the damn interrupt based raster code for the falcon/tt mode as it took to get the stf/ste overscan mode working.

In my case if I find the time to do something, it will definitely use fullscreen + blitter, and there's no way I waste even 5% of my time trying to be compatible with anything else than pure STE.

MegaSTe support on the other hand, yes, 100%, if only because doing some STe code that does not work on MegaSTE is just showing lazy coding practices. (and a significant number of people dropped their STE in favor of MegaSTE just because it was practical to have with the high density drive and built in hdd).