I know this game can be played through with a character who isn't focused on combat at all (namely, intellectual and/or charismatic characters), like Fallout 1 and 2.

But will I be shooting myself in the foot if I do this on my own very first playthrough of the game with the expectation of beating it in a reasonable amount of time (~40hrs tops)?

It's certainly worth a shot. Invest in Charisma/Persuasion (and to a lesser extent, Intelligence) and let your followers do all the necessary fighting (such as during random encounters overland). If you want, you could also invest in the Stun spell to help them out a bit, or for when you're looking to run away instead.

Protip: Be sure to pick up the Worthless Mutt in Ashbury first thing (east side of town; save it from being kicked to death). Once it levels up, it becomes Hell with teeth.