It doesn't run well. Point blank that's the biggest issue to me. Everybody's so concerned with standards and anti-competitive motivations and blah blah blah.
These may be true but I don't even consider them because of the fact that it DOESN'T RUN WELL. Even on the Mac it maxes out the processors and gets your fans running like crazy. Adobe should make it run with decent performance and this issue would dry up and blow away. There would just be no reason not to have it on the phone then.
Adobe just can do it, though. For years they've had their chance to do it and they CAN'T. Nothing else matters. Flash will heat up your phone and quickly drain your battery. Period. If Adobe could get it together (which they can't) they would have it on there already.