I think there's a distinction to be made about Torment's slow beginning.
The Mortuary
I'd say that the very first area of the game is a weak one. Whilst the setting with the non-hostile zombies and all is innovative, it's too big and there aren't any interesting people to talk to until you get to a certain ghost. (Dhal is too info-dumpy. Ei-vene is neat, but that's pretty much it.) And it's too easy to accidentally raise the alarm and end up in a big, boring combat-zone.
The Hive
The first open town-area, however, is great. It's true that you don't get a lot of direction. But it's a marvellous place to explore. If you don't enjoy the setting and the people you meet in the first 3-4 town areas, then I suspect this simply isn't the game for you.
Yes, Torment has a great story. Yes, it takes a while to get going. But no, this is definitely not the kind of story that would work better as a book. It's about the choices you as the player make, the work you put in to uncover the clues, and the way you decide to relate to your past. It's a game that offers quite a lot of freedom in how you play the character, with some great options to play various alignments.
But even then, I'd say that Torment is at least as much about the setting and exploring it as it is about the story and the characters. If you don't enjoy the planescape-weirdness and the more free-form exploring, you're far less likely to enjoy the game as a whole. Particularly the first half of it, since the real story progress only starts happening later.
Combat
The people saying Torment is relatively combat-light are right. The people saying the combat is pretty simplistic are right. But the people who are frustrated by it aren't wrong either. Early on, combat can be quite difficult.
The point about Torment being combat-light isn't so much that you can easily win all fights (though once you get high enough level, you can.) but that you can avoid most of it. There are only a handful of "dungeons." The thugs in the hive will only go hostile if you linger too close and you can mostly avoid them. Because you can run, you can escape most fights. And because you're immortal, it doesn't matter even if you lose.
That said, I do encourage everyone (and vsommers in particular) to switch to a mage as soon as possible. Torment has fun spells, and they definitely make the combat more entertaining.
Oh, and if you find any fight frustrating? Those basic blood-clot healing items you find everywhere also give you damage resistance, and you can use them instantly whilst in the inventory screen. Winning any fight becomes trivial if you eat a bunch and thus become nearly invulnerable for a time.
