Repeating myself briefly from the 4E forum discussion, I agree with this part. This is why I advocated removing ability scores from affecting attack chance, but enhancing their effects on other aspects of the game. Damage is obvious, but it might take some creative changes to really make that pay off the way it needs to.
But on the other side, I think that ability scores ought to be relatively modest at start (showing raw talent) and then improved only in relation to what the characters are. That is, a melee fighter should get occasional boosts to Str because he is a fighter who uses heavy weapons, not use free increases to buy Str because Str gives him something too good to ignore as a fighter. If he fights with a rapier most of the time, he'll get the chance to buy Dex up instead, perhaps.
That kind of cause and effect switch between ability scores and class would be a signficant departure from tradition. So that gives me pause. That mostly removes the last vestige of the original "rolled high Str randomly--so I'll be a fighter". But I'd say that with the popularity of point buy in 3E, we are pretty much there anyway.
If finessed right, it might even bring back some of that tradition. If your starting ability scores aren't so determinative of what you can effectively play, people might tolerate random rolls for them. So what that you start with a 12 Str and a 15 Int. Your fighter will get regular chances to boost Str, hit just as accurately though not quite as hard, and presumably have some niche benefits from that 15 Int that will accompany it.
Maybe it was just us. But our Basic D&D games used random roles (3d6, assign in order). Basic had relatively little determinative effect from ability scores on class. You probably wanted something on the good side of 10 in your main stat, but otherwise you could deal. And we had more varied abilities with class choices.
Not sure how easy it is to get ahold of anymore but there was a game (still one of my favourites) called Powers and Perils by Avalon Hill which I think would give you a great deal of what you seem to want. Attributes and skills improve over time as you use them (and only if you use them). Your attributes also have a starting point and a potential maximum. If you are interested you can check it out here Powers and Perils - Index