Cloakwood. I already mentioned this in a post I was typing before I saw your post while replying to Hormalakh
The Bandit Camp, Cloakwood and Baldur's Gate are content-gated
If anything, Josh Sawyer complained that all the secondary quests in BG2 were in chapter 2/3 with almost nothing after, and that he wanted to do something with more freedom than that (one of the reasons he prefers BG1 to BG2 is because BG has more freedom).
Well technically Josh Sawyer is wrong about that. You can complete optional quest hubs in BG2 in Chapter 2, 3 or 6. I recall doing Windspear Hills in Chapter 6 once I think, because in Chapter 2 and 3 I never spoke to Firkraag at the Copper Coronet. Some of them may be locked, but not all of them.
Personally I don't think that the content-gating in Baldur's Gate 1 and 2 are that different. It's just that in BG2, once you travel to Brynnlaw you are stuck in a linear progression until Chapter 6, whereas in Baldur's Gate - at any point in the game can you just stop your progression and go do something else. Half way through Cloakwood? No problem, exit and go do a wilderness area down the bottom and come back.
I think the natural progression through Baldur's Gate 1 and 2 are kinda similar. I pretty much go from Candlekeep to the Friendly Arm, to Beregost (and the Temple Area), to the Nashkell Area and then in Chapter 3 I do every wilderness area available before going to Baldur's Gate. That is very similar to how most people play Baldur's Gate 2.
So I think the specific difference is just that tunnel of content where you are FORCED to go to Brynnlaw to progress the story and you are FORCED through a linear progression until Chapter 6.
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It has already been stated that PE will have a branching path of progression (from the PCWorld interview in December) and that is why I think that we will get a more tailored experience than we got in the Baldur's Gates.
Chapter 1 will (almost 100%) be the Dyrford and surrounding areas, at the end of Chapter 1 we get access to the Stronghold. I don't think you will be able to go anywhere but a specific number of areas in Chapter 1.
I think that in Chapter 2, a new "region" will unlock and you will get another set of areas that you will have access to - rather than being able to go to Defiance Bay, Twin Elms and Gilded Vale (and wherever else you can go) during the same part of the story.
Once you've progressed the story further (perhaps by completing a fixed number of crit path associated quests in a region), a new region will unlock.
I'd be interested in how crit-path content is being handled if this is the case. Let's say there are five crit-path quests you have to do in Chapter 2 and you need to do three of them to progress. Does completion of three give you the option of progression, or does immediate completion of three progress the story immediately?
I hope that there will be cross-regional content, such as having to go back to the Dyrford in an optional quest while at a later beat in the story.