Aye. It is a matter of preference which path you'll be heading. Sad thing is, with low charisma AoE shapes (eldritch doom, line and cone) become pretty much useless because the reflex saves are so low. And low charisma makes benefits from choosing to take Hellfire Warlock class diminish. His abilities are in fact charisma based (hellfire infusion usable cha mod times per day, hellfire shield blasts are reflex saves with DC equal to 10+1/2 character level+cha mod).
You need to choose your focus. It is indeed possible to play for example a dexer warlock, but it will limit your possibilites, while increasing your defences - later you'll probably run around in padded armor, and even some cool monk/wizard robes when your dex bonus exceeds 8. The downside is lack of uncanny dodge, which makes it easy for enemies to ignore your dex AC bonus.
On the other hand, if what you play is a hybrid of a warlock and a divine or arcane caster heading towards eldritch disciple/theurge, dumping cha might actually be a good option. For example, warlock side focuses on no-save invocations and eldritch blasts, and you pump that int or wis, have considerable scores in dex and con, and leave cha low. Or you could choose to take battlecaster feat, which with a level of cleric (good because of eldritch disciple) or any fighting class (just for a dip) gives you an option to wear medium armors and still not suffer from ASF. Sadly in NWN mithral armors do not change their category to lighter... Believe me, it is kind of awesome to run around as a warlock in mithral full plate (which is then a medium armor), not having any arcane spell failure ^^
This option is especially good if you want to fight in melee. That way you can keep good strength score and still have considerable AC to fight in melee.
