I guess I'm not seeing the argument here. Is it a completely open world? No...but there are multiple paths through (and around) most things here. Examples:
1) When you first land on the beach, there are paths through the area that let you bypass encountering all of the companions.
2) There are several paths into (or around) the crypt
3) There's no reason to go into the blighted village if you don't want to. There are paths to the north and south to go around.
4) There are multiple ways into the underdark
5) many more...
All of these things let you take in as much (or as little) of the world as you want. Other than the one point where you end up outside the druid's grove, everything else felt like I could do as much as I wanted and didn't feel like I was forced on rails to go in some linear path.
