If you're going to "meta-game", then your Fighter's Intelligence doesn't need to be higher than 3, either. I seem to be the only one who says that Fighters need Intelligence 9 so they can use Wands and read scrolls; that's probably because most players never give their Fighters a wand or a scroll, which just goes to show how useless Intelligence is for Fighter. If your Fighter doesn't use wands or scrolls, he doesn't need Intelligence 9. But on those rare occasions when he needs Intelligence 9, we know he can use a Potion of Genius and a Potion of Mind Focusing, and then he can back to not using wands and scrolls for the rest of the game. That's "meta-gaming".
Aside from roleplaying issues, the main reason why people say a Fighter needs high Intelligence is so he won't be killed by Mind Flayers. But let's put this in perspective: how many times do you have to fight Mind Flayers? Aren't there fewer than fifty Mind Flayers in the entire game? Unless I'm forgetting something, there are two small groups and one large group in the Underdark, one medium-size group in Athkatla, one in Spellhold, a large group in Watcher's Keep, and maybe a couple of others somewhere else. Do you really want to put a lot of points into an otherwise "useless" stat when there are other ways to avoid Intelligence drain? Chaotic Commands, Potions of Genius, Brine Potions, and Psion's Blade offer a lot of protection against Mind Flayers. But you don't even need to send in your Fighters to kill them if you have one of the following alternatives: Project Image and Horrid Wilting (Improved Alacrity, Time Stop, and Lower Resistance guarantee success); Greater Deathblow and Fireseeds; hasted Skeleton Warriors; backstabbing Thieves with Potions of Invisibility or a Fighter/Thief with the Helm of Vhailor; summoned monsters and ranged weapons; or a tag-team strategy that prevents any one party member from taking all of the hits. Mind Flayers are certainly dangerous, but personally, I don't let Mind Flayers scare me into putting more points into Intelligence. It just isn't a big deal. Knowing that you don't need Intelligence higher than 3 to beat any kind of monster in the game is "meta-gaming".
As for Wisdom, I don't know of any good reason why a Fighter needs Wisdom higher than 3, but if you ever need it, you can use a Potion of Insight. That's "meta-gaming".
It's debatable whether a Fighter really needs Charisma higher than 3 in BG2. If it's less than 5, I think Edwin will leave the group when you tell him you're going to fight a certain red dragon. And of course, store prices are higher if your Charisma is low. Allowing that kind of information to affect the way you distribute stat points is "meta-gaming". But I just don't see why you'd have your character wear a Ring of Human Influence throughout the entire game. You simply don't need Charisma 18 all the time. Rings of protection, free action, fire resistance, regeneration, anti-venom, Gaxx, and others already mentioned are much more useful. Of course, you can always take off a ring and wear the Ring of Human Influence when you enter a store, but it's even easier to let a party member with higher Charisma talk to the merchant. Honestly, I don't even bother with the Ring of Human Influence at all.
That being said, I'd rather put extra points in Charisma instead of putting extra points in Wisdom and Intelligence. Besides, like kmonster said, with a decent roll of 85 stat points, which isn't that hard to attain, you can give your Fighter 18, 18, 18, 10, 3, 18 (or 18, 18, 18, 18, 3, 10) so I don't know why we're talking about Intelligence 3 or Charisma 3 in the first place.
