I'm no game designer but it just reeks of lazy developers. I seem to remember a time where everything was rendered on the game's engine like it was supposed to be.
EDIT: I actually don't have any FPS issues, other than all around lower than I'd like due to my 3 year old budget gaming PC, though it may be because I already messed with my flash settings thanks to another recent game that had massive FPS issues due to it's UI.
Edited by Kassatsu, 05 March 2013 - 05:19 AM.