1. Nobody understand how to use those filters. To have people using features in their games, they should be simple and logical. Plus, every layer of filters is possible cause of extra lag and another wave comments about "flash game causes my computer to crash".

2. F10/AS3 only. Plus its not possible to create or modify through code and have interactive IK/bones. I am sure animators could use IK if they would ever switch over to work with AS3 but for games they are useless.

F11 has also number of potentially cool features that could fail. iPhone publishing sounds nice but has awful perfomance and number of annoying restrictions. Time spent on fine-tuning your Flash game to run on iPhone could be better spent rewriting it as native iPhone game.