I was re-reading
d20 Modern a bit the other night--just flipping through it, really, and I remember being surprised by a little chart in the Gamemastering section of the book where it says, essentially that 15-point buy is "regular", 25-point buy is "heroic" and 32-point buy is "super heroic."
In any case, I find the semantic quibbling somewhat pointless and tiresome myself. Yes, I understand Crothian's point that "heroic" comes from doing heroic things, regardless of what your stats are, but clearly that is not the sense in which the word is being used, so it's a bit of a non sequiter to bring it up. Communication is not enhanced or enabled by sticking to your guns about using a different definition of a word that clearly is not the one referenced in the conversation by everyone else. It's a bit as if my GM tells me he's starting up a new D&D campaign and I keep trying to play a Runequest character.
Heroic, in this sense, means capable of doing things that normal people are not capable of, i.e., higher stats. I like the idea of the... what was it called again? The Stormwind Fallacy? I agree that interesting characters are usually completely decoupled from their stats in terms of how interesting they are or aren't. However, just being interesting isn't the only factor in terms of how
fun they are to play; a character that is unable to do basic tasks required of an adventurer probably isn't going to be very
fun to play in a standard D&D type game; he'll probably be really frustrating, actually.
And that goes back to the other question above; can you play a 15 point buy character from 1-20th level? Absolutely. One of my pet peeves for the d20 version of the game is that folks are now so completely reliant on the CR and EL system; all you need is to make sure as a DM that you are aware of the capabilities of your PC and construct challenges accordingly, and you can play any type or mix of characters you want. We used to be able to judge that all the time without much in the way of mechanical guidelines; I don't know why it's such a challenge now to look at a particular monster or encounter and say, "y'know what? Even though that CR is spot on, my group won't be able to handle this because they lack the appropriate spell, etc."