Let me rephrase what I said: The reason a lot of people (myself included) consider PS:T on the same level as the behemoth Baldur's Gate 2 is mainly the writing (and by writing I also mean all the characters, the setting and so on).
Baldur's Gate 2 beats the living daylight out of PS:T in pretty much every other aspect as far as I'm concerned, yet I still consider PS:T one of the truly greats, and that is because PS:T is so far beyond BG2 in terms of writing.
A few examples of where BG2 beats PS:T
- Combat (by miles)
- Music (one of the best soundtracks I've ever heard)
- Overall polish and quality (yet again by miles)
- Variety in terms of spells and abilities
- Variety in terms of loot/gear
- Overall scope (BG2 is massive)
- Smoother interface
Sure, even with poor writing, PS:T would redeem itself a wee bit due to the original setting and concept, but that alone is far from turning it into a classic comparable to games like Baldur's Gate 2.
That's why I like to call it an interactive novel - other game elements are certainly present, but they're all merely "okay", while the writing is possibly the best we've ever seen. It's the one reason to play PS:T instead of other alternatives.
Edit: In case people lack the ability to read between the lines or remember what I've written previously - I've never claimed PS:T is literally an interactive novel. It's a figure of speech to point out the extremely heavy emphasis PS:T has on writing.
Edit 2: My original quote for reference:
The writing. PS:T is more of an interactive book than a game really. The characters, the plot, the world itself - all extremely well written.
The gameplay is not all that great though, as it's basically a sluggish version of IWD/BG.