If an x86 implementation was imperfectly compatible with Intel CPUs, nobody would buy it. Gmail, on the other hand, is a massive market success. It is those who shout that IMAP must be exactly and only whatever mutt+uw was doing in 1997 who are on the wrong side of history.
It's a free email account, it is not at all clear that "weird IMAP" is core to that success?
Certainly I moved away to Fastmail, which has better IMAP support (but mostly because Google having full control of my email address was becoming too big of a risk and Google Apps is expensive for your own domain).