Quote Originally Posted by HMS Invincible View Post
That's avoiding the question.
More jumping the gun IMO. Skipping steps for the sake of brevity, only to have to go back and spend lots of time elaborating, is a specialty of mine.

To go over the stuff I skipped:

1 - Excessive metamagic reduction creates excessive damage (and/or excessive riders on top of the damage). Your post details it, as does googling the Mailman sorcerer.
2 - If your group's op level is okay with that sort of damage (i.e. one-shotting things several CR above the party level) then all is well. No bans or changes needed.
3 - If it is not, then you need to tone things down. Your initial post suggested banning Arcane Thesis and its ilk . . . which works, but due to the difficulty of utilizing metamagic in E6, keeping it around in a non (or less) abusable form is worthwhile, hence my suggested alternatives.

Sorry for the confusion!