No, but many of the "Firefox crashes a lot" are caused by profiles who have gotten corrupted over the years, and many of the "it eats 2G of RAM" are caused by that and extensions.

Old Firefoxen also tended to fragment their SQLite databases heavily on disk (and in some cases, internally as well), which can show as sluggish response and "hanging" whenever disk I/O is involved. There were changes to ensure that some critical database files don't get fragmented any more, but if you already have those files from an old install you're SOL as it can't defragment them while its using them.

If you have serious performance or memory issues with Firefox, and you're a longtime user, at this point cleaning your profile is probably at least as likely to help as waiting for the next version.

Edit: Just to clarify, the manual cleanup is necessary because uninstalling (and reinstalling) Firefox never deletes your profile. This means that a serious problem can never be fixed by a reinstall - a behavior that probably should be changed.