What is it that makes Flash be less desirable, besides not playing on an iPad?
Extend that to not playing on most mobile devices in the near future, and performing fairly badly on many of them now. The latest news is that
1. Adobe has stop development of Flash Player for mobile devices.
2. Microsoft has said that it will not support any plug-ins (such as Flash Player) on the mobile version of Windows 8, intended for tablets
3. Google has just released a version of Chrome for Android, which looks to be a far better replacement for the current Android browser, and it has no Flash Player support, due to item 1.
On the other hand, some desktop browsers do not support HTML5, and so might do better with Flash. To be specific, the problem browsers are Internet Explorer before the current version 9, still used mostly by:
a. People still using Windows XP and its originally installed default browser IE 6, and who never update the browser despite Microsoft pleading with people to make the free upgrade and rid the world of IE6.
b. People in a certain large Asian country running pirate versions of Windows XP which cannot be upgraded.
So, decide which group of customers you would rather miss out on: the people who buy and use the latest mobile devices, or the ones using obsolete software on aging hardware.