Dunno, I didn't read it. I never read any of Jack7's opening posts, they're always far too long for a message board.I thought the question was pretty clear up in the first paragraph. Is there anything in the intervening impenetrable wall of text that muddles it up?
I don't think the heated arguments about editions are based on "purity," however, but are more about genuine loves and loathes of mechanics and fluff that vary across the editions.
I voted for "impurity"- considering how I've tried to use HERO's martial arts system with virtually every version of D&D, how could I not?.
The question of how "pure" you game is can be interesting. However, I think putting it as "purity vs innovation" is phrasing it inaccurately. Having an impurity does not imply you are being innovative.
Can I get a tl;dr version?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.