Flash Lite doesn't support AS3 yet. That's a major problem for me since I don't develop for mobile platforms - and having limited AS support bothers me since I'm in Adobe Flex, which means AS3 only mostly.

Having the full-blown Flash plugin is a boon to the Maemo 4 (Chinook/Diablo) platform, and seeing such a baby step in Maemo 5, bothers me.

The rivals in this case would be Android... and it supports Flash Player 10 - such as the HTC Hero and continuing forward.

Now accessibility and 508 compliance... you truly wouldn't use Flash - it's possible but lord it's a pain.