Yes it's not a breathtaking stuff, but still some improvements over more lineal, combat oriented quests from previous games.
Eh. You had multiple ways of finding Bandits' Camp in BG1 and an option to infiltrate. Charm spell used outside of combat could give you plenty of additional background info, there was plenty of quests that involved saving people turned to stone (from Branwen to the guy with Balduran Helmet). You had actual heist-type quests for thieves. Not exactly non-combat, but there were some little touches like dispelling weapons of battle horrors etc
In BG2, aside from what ga♥ mentioned, there was an option to uncharm the bodyguard of lord d'Arnise, cast healing spell to defeat the monster in underground temple area, probably some other instances I don't remember. They were pretty consistent throughout the series.
Sorry, I never enjoyed ToB, too linear, too much "Hello Child of Bhaal", no content, no quests, Saradush which is supposed to be a city, literally the size of a village in fuckistan, no reactivity.
I like Throne of Bhaal for what it is, cheesy, over the top send off.
Saradush I thought was probably the best part. Great atmosphere of the siege. I mean, medieval cities/towns were often quite small, Beregost in BG1 is basically the same size. I get it that in official Forgotten Realms material it was maybe supposed to be more grandoise, but - who cares, really?
There are also retarded plot holes, like Abizagail being a great wyrm (so at least 1000 years old?) and being a bhaal spawn, with another great wyrm son, Draconis (which is misteriously not a blue dragon even if the father is one) so put another 1000 years, when Bhaalspawns are supposed to be of the same age more or less ....
It's not like BG was overly consistent at any point. They were playing fast and loose with the setting from the start. Honestly, it's hardly a big problem, since you can easily assume that Bhaal was making preparations for a long time. I don't remeber it was ever specified, when he started.
Either way, establishing a timeline seems to be prevalent problem in crpgs. Even in PS:T, while it wasn't evident on the surface, if you pay attention to some quests (mainly those that concern the paranoid incarnation, I think), you can spot some contradictions. And it's blatantly obvious from the start, how messed up the timeline is in NWN2 (the war that happened maybe two decades ago and no one remembers anything, even better, people managed to confuse who fought whom, while various NPCs refer to it interchangeably as something recent or from distant past). I would guess it's caused by the specifics of development - different writers working on different parts, having ideas evolving in slightly different directions...