Like some other people have pointed out, I think this house rule would actually cause the opposite problem from the one it seeks to fix. With this rule in place, it's pretty foolish to have a key score that's anything higher than 14
Eh... why? The stat still applies to your damage, which I understand most people like, as well as your relevant defense for that stat pairing (also useful), class skills, etc.
For example, a rogue with a Dex 14 is worse at damage, reflex, AC, initiative, stealth, thievery, and acrobatics... things that a rogue might actually care about. Also, I hear there are feats a rogue might want based on Dex. Things like expanded crit range, and such. And you could maximize Str instead of Dex, but that's damage only with sneak attack instead of Dex which is all the time, more with basic melee, but less with any ranged, etc.
It would, OTOH, make it possible to have a rogue that cared about Int more... which is, I know, a truly disturbing possibility, but one I'm willing to accept.
It would also make the more 3e style stats a little easier... more well-rounded 13s and 14s, cause it's less costly to do so kinda thing.
Just because something is different doesn't make it automatically bad. I'd been thinking of a variant on the suggested rule and was going to make a post about it, then found this thread... and the only potential problem I'm seeing so far is actually Twin Strike, maybe.