For some reason, I really, really prefer IWD2 over even BG2. Maybe it is the pseudo-3.x system, maybe it is the race and class choices, or maybe it is just Capitan Garlic's hilarious LP of the thing, but IWD2 made a bigger impression on me than BG2.
IWD2 would have been OK if it didn't repeat so many areas from 1. Tbh I don't care about revisiting those areas. I never made it to 2's Dragon's Eye, but I hear it's a Guantanamo-like experience.
You have plenty of frustrating things not present in the BGs, like Battle Grid, or the fight with the dragon in Chult. The dragon is barely OK, since you can actually do things to get there prepared (like playing solo with an ubercharacter), it's barely the same thing as Yxunomei in 1.
I haven't tested the HOF mode extensively, but maybe the game shines more with it. I only know normal mode sucks, and it's frustrating. It's like your DM suddenly went nuts and is hellbent on wiping out your party. For example, I hate when the pull mechanic is broken. In IWD2 enemies get to your back lines in a breeze. The BG's way was also retarded, "fight the nearest enemy", but it wasn't as frustrating.
Anyway, it's a game you have to take with the caveat of powergaming it heavily. BG can be played with less powergaming. Also in BG there's more wealth of cheese for everyone.
But I understand that powergamers love IWD2.
Also, just a piece of history: the highlight function in BG2 was brought with TOB. So if you want the Watcher's Keep, for example, you also get it. Using it or not is to your discretion. Like TOB itself...