The real problem is that Mozilla lacks a Mac OS X usability advocate with the authority to expedite sensible solutions to these kinds of problems.

As we all know, the standard OS X shortcut for moving backward and forward is Cmd+[ and Cmd+]. The Cmd+Left/Right shortcut for moving backward/forward is decade-old cruft (even though Safari still conditionally supports it).

If the Mozilla platform cannot handle supporting this cruft on top of the standard Cmd+Left/Right text editing behavior, then at the very least remove the cruft. Instead, the problem is allowed to linger for years and years as people bicker back and forth about what to do about it. That shouldn't be acceptable to anyone.