I'd say just let the Player play what he rolled, and don't sweat it. In the future, if you want a "balanced" party, tell the Players that they
could roll, if they wanted to, or just accept your default array: 18, 17, 16, 15, 14, & 13, arranged as desired, and modified for race... Most will take the default, and your party is balanced!
Need to balance an already-existing party? Pre-plan your treasures!
An item usable only by a certain race, class, sex, or alignment (or group of alignments) chops 30% off the price. So if your "Super-powered" Human Fighter is male and NG, and is overpowering your LG Human Paladin male and his male NG Elven Ranger buddy, you can add a masterwork bow that functions as +2 only for Good Elven Rangers, for example, and instead of it being worth 8,000 GP, it will be worth 800, because only the Ranger can use it.
Likewise, wands will go to whoever can use them, scimitars almost always to a Druid, maces to Clerics, etc. While Uber-Fighter might want the bow, scimitar, or mace, the fact that it acts as only Masterwork, for him, will pretty much assure that the PC who "needs" the boost will get it.
Of course, this looks contrived (Duh!)... The easiest way to work it in is to have a friendly NPC (Wizard, Bard, or Sorcerer works best) inform the appropriate PC as to the existance of the item, give it a history, and give the PCs some idea(s) as to its possible whereabouts. Then they can "quest" to gain something only usable by them.
While the GM can throw in wands, scimitars, maces, etc. at any point, the other items usable only by a few should either be introduced as legend, or in the hands of allies or enemies.
Two examples: A Druid's Staff is usable only by Male Druids of Neutral alignment... Note that Neutral allows NE and NG, as well... So a NE Gnoll Druid could wield it against the party, and once it is killed, another Male Druid (all of whom are Neutral) could take it over... Or, it could be sold as a MW item... Or, it could be traded to another Druid for curing, etc...
A magical Hand-Crossbow usable only by an Evil Drow Priestess, on the other hand, will be wielded against the party, and generally be useless to them. While it will radiate evil Abjuration magic, they won't be able to get it to do anything, and won't even be able to sell it for much more than a MW Hand-Crossbow.
As a third example, if the Paladin and his master/trainer are both LG Human Paladins, the master could easily be killed, die of old age, be slain in battle while the PC is absent, or just retire, leaving the sword to his protege'... who is one of the few people who can actually USE it!
This also solves the problem of PCs looting the bodies of other PCs, or stealing from their own party... Items of this sort will not generally be usable by the other PCs!
In your case, the 10% pricetag can also be used to balance the party, assuming your PCs figure out what the items can do. If you really MUST balance that +4 STR Bonus, you can give a +2 sword usable only by a Good (Race, Class), and usually only one PC in the party will be able to use it. Now your Good (Race, Class) with +2 STR has the same To-Hit with this sword as your Uber-Fighter with his +4 STR and ordinary weapon.
The easiest way to display this to the PCs is to describe the item found as masterwork, and otherwise normal. If they detect magic, it will radiate as usual, but (again) do nothing... When the PC who meets the three restrictions picks it up, though, it will suddenly glow, as magic weapons often do... This is a pretty clear indication that only that PC can use it. Later visits to a higher-level Wizard or Bard can confirm this...
Well, there're a couple of ways to "solve" your "problem", if any of them seem good to you...