Ran across this interesting post talking about why flash lite isn't on the iPhone. They list (from an unknown source at Reddit) a few of the reasons why Apple rejected flash lite for their iPhone with biggest issue being that flash would suck the iPhone's battery dry in less than one hour. Not a good sign for anyone looking to use flash for their main user interface on a mobile / battery device. Plus it also points out, even if you aren't battery dependant, the load flash will put on your CPU.
Jason