Yep, you're describing d20 Modern. I didn't love the system. It worked fine, but for me it lacked flavor and wasn't even close to evocative. I don't want to play Constitution guy, I want to play a knight thundering across the battlefield.
I've never, ever, claimed to be original; my memory is too poor to recall where I left my pencil five seconds ago, let alone what I've read or played over the last twenty-odd years.
I do vaguely recall playing d20 Modern briefly and thinking pretty much the exact same things, though. But I'm not advocating losing classes or even basing classes on abilities, simply that they come before choosing classes so that powers/feats/skills, etc. can be tailored better towards that focus. In other words, fitting a round peg to a round hole, instead of what I often end up having to do with the rigid systems of D&D, which is to ram square pegs into round holes.
This would actually open up more variety rather than close people in on 'builds'. Not many people want to play a character that doesn't have good synergies with its class abilities. How many rogue players would play a rogue with a Dexterity of 14 in 4e? And if they did, even I would call them silly for doing so. But maybe the rogue has everything the player wants, but he wants to base his character around Wisdom and not Strength or Dexterity or Charisma because that's not how he envisages the character.
The amount of times I've had to ignore ability scores for the sake of my character vision is pretty much on a 9/10 ratio to the point where often I just don't play those characters and end up going with some CharOp build since it's just easier to justify in my head how the character looks on paper and how that translates in my imagination.
A good personal example of this is one of my favourite characters of 4e who is an Avenger. The Avenger class is PERFECT for my character concept with all but one flaw... I simply don't perceive him as being Wise and his Strength score is too low because I have to prioritise Wisdom and Dexterity. If I compromise those abilities, then he doesn't perform the way I envisage him working. So I'm caught between either not playing him because the stats don't line up with how I see him, or ignoring what the stats say and envisage him as being 6'5" tall and exceptionally muscled despite his 12 Strength and being a crazy, charge into the fray and pursue his quarry with blind vengeance and raging hatred despite his 18 Wisdom.
Now, if I could build that very same character with the very same class and powers, using Strength as his primary and Dexterity as his secondary, and by doing so having those abilities work just as well as if he'd chosen Wisdom + Dexterity, then I'd be a much happier camper.
This notion of straight-jacketing into 'logical' roles based on 'logical' assumptions, ie. that a fighter should be strong, a rogue should be dexterous, a wizard intelligent, etc. leads to illogical and unreasonable restrictions. Not every fighter has to be 18 Strength and 16 Con.