J2ME never had near enough functionality for the apps to do anything very interesting. I do not recall a single J2ME app apart from Opera Mini which was worth using. All the good (by the standards of that time) apps were non-J2ME, at least on Symbian and Windows Mobile.
So even though it was fast enough, I wouldn't compare it to Java as it exists for Android now.
You need to go to Japan more often. I worked quite a lot with NTT DoCoMo and they had amazingly useful games and apps. Everything from a bank machine locator to physical vending machine purchases (with NFC).
They had motion sensor support in J2ME devices that they used mostly for fishing/golf games circa 2003-2004 (don't hold me at the dates my memory is the gray equivalent of Swiss cheese).
Anyway, J2ME had a lot of levels CDC was pretty much Android equivalent but it didn't have GUI API on top of it because Sun disallowed MIDP on top of CDC and didn't offer anything other than AGUI which nobody used... I can go into endless details here but generally, the reason J2ME failed was that it was a tool built in 1999 with a single moderate update in 2004 and nothing else!
The only thing that hindered J2ME on my old flip phone from 2006 was the carrier disabling all the interesting APIs. If Android had been based on J2ME and put control in the hands of users instead of carriers, it would be a much better system IMO, especially in terms of security.
