I remember well the effects each stat has on the game. But I think you overestimate the impact that a weak PC would have on the overall party. Regardless of what you roll, the NPC's are going to be exactly the same each time, and you have 5 slots you can fill practically from the beginning without much fighting. SO they can cover for your PC till you get the Gauntlets of Ogre Power in the Gnoll Stroghold, etc. You know what I mean. It really shouldn't prove to be that tough.

Perhaps I should make myself clearer; even if the companions do cover for you, a character with low stats is still at risk of dying constantly early on. Take the mage I rolled up last year; maxed out Dex and Int, 16 in Con, and even when I held back and put Khalid on melee duty and tried to hang out behind the archers when my spells were exhausted, I still attracted my fair share of kobold arrows which wound up killing me plenty of times in the mines. Factor in the wonky pathfinding and its baffling tendency to push the most squishy of characters in front whenever the path becomes narrower than a two lane road or is full of obstacles (i.e. trees) and the odds of my mage drawing aggro from every ranged attacker in an overworld encounter and subsequently dying from doing an impromptu impression of a pincushion went up exponentially. If he had been rolling with the stats of the hypothetical 9 Int mage, I'd have been surprised if he ever made it out of Candlekeep.

Sanctuary

In BG, I mostly play mages. They only become useful after they acquire skull trap or fireball; up until that point, I'm effectively playing with five party members.In the end, I mostly have two mages.

I'm sure I could finish BG1 and BG2 without actually having a usable player character; so in the end, the stats don't really matter. Therefore I don't spend a lot of time re-rolling stats. For a mage, I go with this:

STR: 9
CON: 9
DEX: 9
WIS: 15
INT: 18
CHA: 9

That's only 69 points. Therefore, as soon as I roll somewhere in the 70's, I'm good to go when playing a mage. I do similar things for other classes, if I play them.

Oh, and I never roll a new character in BG2. I always port over my BG1 character.

I'm currently running a game in BG 1 with a cleric/mage multiclass halfelf PC:
S 6
D 6
C 6
I 9
W 9
Ca 3

First thing I did was to take Monteron in the group and had him pickpocket Algernon's Cloak at the Feldpost Inn. Then I kicked everybody from the party and pretty much soloed all the quests you can do before completing Chapter 1 by charming whatever non-joinable NPCs or Monsters are in each area to power-level my PC asap. Example: you can charm Flaming Fist guards to help for in-town quests, or in the wilderness areas there is usually at least 1 non-joinable NPC who you can talk to or a Carrion Crawler or something, then charm them to help you clear the area using the Cloak.

I've been all over the southern regions and have got him to cleric 5/mage 5, just about ready to form the true party to move the main story further along in the chapters. Between the Cloak, Ring of Magery, Ring of Holiness, backed up by Gauntlets of Dex, Mithril Chain +4 and Warhammer +2 it's been pretty easy so far.

Cleric spells: Sanctuary, CLW, Entangle, Strength of One. Mage spells: Mage Armor, Grease, Web