Well, the theme is different, the tone is different, and combat is much harder, which fits the atmosphere well. BG was a walk in the park.
You're sort of exaggerating now. A blind, first run of BG1 base is pretty hard and unforgiving. Even if you min-max, your THAC0, AC and saves are high (a bad thing), and so the RNG wreaks havoc on you. Level 1 mages have 6hps max and fighters 14hps max. You also have very poor equipment, scale mail max for fighters and metal weapons that fall apart in your hands due to tainted iron. And there are three chances to be TPKayed or at least mostly decimated in the second and third maps alone: wandering ogre, waylaid by bandits, mage on the stairs.
ToSC assumes 89,000xp. Fighters have almost maxed out hit die, proficiencies and ApR. Arcane and divine casters have a spellbook full of options and can summon mobs of undead minions or beasts at will, thieves can backstab at x3 and can stealth anywhere and pick any lock or trap, you already have +2 weapons/armor and your fighter/mage can probably buff himself to -20 so he only gets hit on a crit.
At that stage the only difficult enemy is Shandalar and he's not mandatory or even designed as a target other than to be pick-pocketed for his OP spells.
The expansion just complements the base and adds in a great megadungeon. Might I add too, ToSC has been sold with BG1 since 1999, which I believe is the year it was released. When people say BG1, from my experience they almost always mean ToSC included.
You seem to have an odd hate-on for the base game, but each to their own. I think I'm done espousing its virtues.
You don't have any special powers and your inner awesomeness (or lack thereof) isn't the main theme of any of these games
And you hardly feel like one of the Bhaal's Chosen until a fairway into the Saga. Sarevok seems to be the special one in BG1, and you only realize you're special towards the end of SoA when you shift into Slayer form and get a glimpse at your pocket plane that carries into ToB, where you start to realize you're the most worthy Bhaalspawn to take the mantle.
I don't know. I thought the plot was idiotic. Complexity for the sake of impressing people, like the last 007 plot. Contaminated iron, really? From one mine? Why not contaminate bricks and then sit and watch the chaos as houses start falling apart, then start selling clean bricks and make a fortune?
Well, it wasn't about money to Sarevok, was it, who was manipulating most of this for big-picture ends. You sort of can't wage wars that invoke murderous gods with bricks and houses. Remember, it was a conspiracy to create an iron crisis so that the Iron Throne could be looked upon as being a key factor in the region's military "defence", it was part of a larger political manoeuvre to facilitate Sarevok's divine ascendency.
A large pool of recruits doesn't mean much when they have the depth of cardboard cutouts.
They're supposed to be one-dimensional, its tongue-in-cheek. Direct pop-culture quotes abound, which should have given you a hint. And a large pool means alot in a combat and adventuring sense. I didn't particularly like the long-winded banter and romances in BG2, in fact they annoyed me and got in road of adventuring. About to fight a lich, Anomen wants to cry on my shoulder, etc.