After finishing IWD I've started IWD 2, had a blast rolling my party and am very pleased with the changes to the ruleset. However, the amount of scripted events triggering with my invisible Thief scouting ahead is driving me nuts. I'm only in chapter 1 on the Shaengarne Pass and am pretty close to shelving the game due to that. Over the last hour or so, the ostensibly invisible Thief triggered several conversations with Torak, both of the captive Druid couple, the woman with the mill quest, the Troll in the cave and now the Wererat leader on the pass.

My question: Is the entire game so scripted or is this some kind of misguided extended prologue? I'm so torn. There clearly is a brilliant game underneath which I really want to play but atm going on feels like a pure waste of time.

That is what you get in linear games like Icewind Dale (1 and 2). You have to live with it.

Thanks Hickory, but that's unfortunately no answer to my question. I have played IWD and there are instances of similar scripting, but they are few and far between. Nothing even close to the sheer volume at the start of IWD 2.
It also has nothing to do with linearity. Just because the player can't skip a particular encounter doesn't mean the designer has to force a conversation script to trigger when an invisible Thief comes into range. It's inconsistent design, plain and simple.
Thing is, in IWD, different chapters were designed by different designers. Some of them were good, others were bad. See the inconsistent use of "call-for-help" scripts in IWD or the awful unavoidable traps in the Vale of Shadows which thankfully were skipped thereafter.
My hope is that the incompetent guy responsible for parts of IWD 1 was fired after "designing" chapter 1 of IWD 2 and someone competent took over starting with chapter 2.

I simply meant that it is more prevalent to get that kind of forced interaction in a linear game like IWD -- it is very rare in non linear games like BG; it only occurs in mission critical instances. But you seem to already have the answer to your own question anyway, so there's not much else I can add.

Yes, forced interaction is probably more prevalent in linear games. But the question is: Within the specific game IWD 2, is it more prevalent in chapter 1 than in the rest of the game? A question I unfortunately don't have an answer to myself, having never played the game before.

Fair enough, though unfortunately I don't have figures, and I've never compared the chapters, or the games, in that way. What I can tell you is that it does happen in other chapters. I cannot be more specific, sorry.

No worries, depending on playstyle and taste I can see how other players might not be bothered by this at all.
Maybe someone had a similar problem and chimes in here later. Otherwise I'll wait for a couple of days and see if I can get myself in the mood to just overlook the issue. If not I'll simply drop it. Sad as this would be...