I disagree, totally.

Basic knowledge of what each category is (small weapons as opposed to big, light armor to heavy) and a little common sense is all you need. If you are ranged obviously don't load up on strength; if you are a tank don't full up on intellect. Basic stuff and I do great with these games.

I never thought that could be the case. Do you have an article that explains this and similar stuff that might be necessary to know in D&D games? I mean to play through Baldur's Gate 1+2 some day down the line and it might help when I create a character.

I must say I can't stand the idea that kind of design choice that numbers between doesn't do anything, every number should matter otherwise what's the point of leveling up? Just to get to one level that will make a difference? Then it's all unnecessary filler content. One of the worst pet peeves of mine when it comes to numbers in any game is diminish effect. If I'm high level and pick random skill to increase let's say 50 -> 51, nothing happens, only 51 -> 52 there's actually a change and even that can be less than a 1%. Talk about superfluous content..

No real explanation. Just one of the quirks of the old AD&D system. Much of it made little sense (although for some reason it remains my favorite D&D system to date). As another example, multiclassing is restricted to non-humans only, and the race determines exactly what you can combine as far as multiclassing goes. Dwarves can't be mages, Elves must have a minimum of, I believe, 8 CHA (for no apparent reason), etc.

Humans can dual class, but if you do so, you can never raise the level of your original class again, and you lose all functionality of the old class until your new class is one level higher than your old one.

Levelling up in the AD&D system does not give you any skill points (for most classes) or attribute points. It only affects your HP totals, your THAC0 (your 'to hit' chance) and your saving throws (for thieves, you also gain a certain number of percentage points in your thieving skills, which you can distribute how you like). Casters also gain new spell slots and/or spell levels.

It's an odd and many times nonsensical system. But it somehow works (at least, I like it).

Some reading is necessary to know what race to select, what are the important stats for what kind of person... but beyond that, the good thing about BG and IWD games is that as you control a party, you get to experience different aspects of the gameplay, like one of your characters being a powerful melee tank, another a weak spellcaster, another a thief that scouts ahead etc.

With one-person RPGs, you may need to decide what kind of experience you want for that gameplay run, e.g. more about strength or conversations etc.

I think this happened to me in Fallout 2. It dawned to me that your Charisma decides (mostly) how many companions you can have in your party. IIRC the game gives two possibilities to increase you Charisma (through a perk, and finding and using a Blue Memory Module). I obtained both so I could push my charisma from the original 6 to 8 I think... but the move from 6 to 7 didn't affect my ability to have more companions because apparently it is decided by a formula "number of companions = CHA/2" rounded down, meaning that you can have only three companions both with CHA 6 and 7.

I guess I was lucky though that I had CHA 6 and not e.g. 5, because then I would have ended up with CHA 7 and be annoyed of not reaching an even number for it.

I guess extra charisma has other effects too than merely the number of companions, but to me that was the most important thing with it.

'Brutal' makes it sound as if this was something critical to success. I'd be more inclined to call it "disappointing", since you can do it a lot better on your own, but I don't think the recommended choices actually ruin your character. NWN is still pretty easy, either way.

Or do you have any specific examples of how the system can mess up your character?

Well, 'brutal' is just my choice of words. I spent several years playing nothing but NWN and building characters (incorrigible powergamer here) and I found the 'Recommended' choices to be just that: brutal. Things like putting points into Parry (a broken and almost 100% useless skill), selecting Two Weapon Fighting without Ambidexterity. Power Attack with low STR and high DEX, or Weapon Finesse when you have higher STR than DEX. Concentration on a Fighter. Things like that.

You can pretty much adjust to anything the Recommended options do to your character, but it's far better for someone to just get a grasp of the basics of the game and make their own choices. Not in a powergaming or even min/maxing sense, but just so the choices they make actually fit with and benefit the character they want to play.