Invoker...I love ya, man, but you are an outlier. No one should balance game play on the weakest or strongest, but instead balance for the tallest points on the bell curve. You can't expect 80% of the players/builds to have the same experience that you have. I know you are good at this game and tend to think everyone should be, but they just aren't and probably won't ever be. It doesn't make them (or you) wrong, you all just have a different experience and vantage point.
Since this is not a competitive game (quite the opposite, in fact), your approach makes a world of sense. But I didn't suggest otherwise, in the thread.
Aaron's request was for options, and flavor. If anything, this is about finding something attractive enough for Sorcerer, and thus worth taking/tempting RP-wise, but still inferior to the top multiclassing options (which are overpoweringly strong, so not a challenge).
I think the idea is to find something either good enough, or different enough that it can be worth playing (and thus, developing). It has to require more pure Sorcerer levels, and offer something different than the PrCs around (because nothing similar can compete with them on what they offer, and still remain balanced).
Aaron's and Sun's ideas are interesting, but I am a bit concerned about the feat-heavy investment. Sorcerer does not have many feats to "waste", and pure Sorcerer will certainly want CE/ICE already, plus at the very least 3 metamagic feats.
Perhaps a good way to go would be bloodlines that grant metamagic feats AND other benefits (Skill bonuses + Metamagic in one single feat, for instance). That would probably be a different path, worth exploring.