Most BG2 players are powergamers who consider BG1 as work to be done in order to be able to get a more powerful character in BG2. (If there was BG3 they'd consider the goal of BG2 the ability to start BG3 with a stronger character too.)
Don't be one of those. BG deserves to be played and enjoyed as the great game it was, even if you're a powergamer try to get your character powerful in BG1, not after the game is over.
If you want a strong BG2 character just use an editor on your starting character then, it's easier and has the same effects, don't spoil your BG experience for it.
I actually prefer BG1 to BG2. However, I do try to play the entire saga, through to Throne of Bhaal, with the same character. Also, I HATE using trainers or hacks, unless it is to correct a problem in the game; mods are fine, but I refuse to edit my character at all once I have created him/her in Candlekeep. Thus, I like to get the character the way I like him/her before I even set foot into Candlekeep, so that is where I was coming from with my advice. Honestly, though, I think a well made character is more important at the lower levels anyway, since any mistake is that much less forgiving.
As for the rolling: A total score around 80 should be way enough to enjoy the game without too many difficulties. Remember, it shouldn't be about the perfect character, it should be about YOUR character. :)
But, it is just so EASY to roll a 90 or better, that's all. Since the MINIMUM stats the game will ever roll you in character generation is a 75 in total stats, someone could get an 85 within 5 minutes, tops. Why not just roll for 30 minutes and reduce potential hassles (like being able to increase STR on a mage so there aren't as many carry weight problems, or putting some INT/WIS on a fighter to help will appraising minor items once in a while). Making the game less tedious (yes, I find inventory management and having to Identify every minor potion to be 'tedious', sue me :P) in one way or another is not going to detract from the role-play experience one bit, imho.
As a sanity check, for myself, I decided to roll up a couple characters and see how long it took me to get to 90 in all stats. I chose a human fighter and a half-elf cleric/ranger as my test cases (the hardest and the easiest to get good rolls for, iirc)
4 minutes -> 84 total stats
6 minutes -> 86 total stats
8 minutes -> 88 total stats
11 minutes -> 90 total stats
Before first roll -> 85 total stats
8 rolls -> 88 total stats
13 rolls -> 91 total stats
Note that the Cleric/Ranger was in number of rolls, NOT minutes.
Every other race/class combo is going to fall somewhere between these two. I hardly think rolling for 10 to 15 minutes is that much of a hassle. Not if it will save some aggravation later on down the road.
I don't want to tell people how to play the game or how to have fun, but I do want to make sure they do everything they can to maximize their enjoyment. If they don't care about stats, then they don't need to bother rerolling. However, if they DO care, I thought some rough guidelines might help a little.