Managing any project with thousands of contributors is very hard - namely, duplicate bugs, low quality bug reports, bugs that are no longer valid given OS or version changes, etc. I can't imagine how hard it is to manage something on the scale of Android, where it's so consumer-oriented, half of everyone with a phone (roughly) potentially could be using the bug tracker. There may be some interesting room to build a b…
Of course that doesn't solve the difficult matter of actually fixing the bugs, but I'm sure the Android developers would sincerely appreciate it. Closing duplicates or reports with little information sets a standard for the bugs that do get fixed.