The only BG game I've actually replayed multiple times so far is BG1 (which I had bought shortly after the initial release).
I tried re-doing BG2 again some time ago, but whilst a good game with superior technicals and quest design, it reminded me that everybody seems to think about the 2nd chapter when gushing about it most of the time. The entire middle section is a fairly linear combat heavy dungeon romp not lending itself as well to replayability imo, which technically, Icewind Dale also did better, as far as I am concerned. Throne Of Bhaal in terms of structure / gameplay I generally didn't much like even back in the day, despite the excellent wrap-up of the adventure at the end.
The following is less about replayability, but more a prefence: To me BG2 also marked the beginning of Bioware moving away from recreating a TT adventure feel and going into a more "interactive movie" kind of direction, as not only did they introduce more traditional cutscenes (as far as the Infinity Engine could handle them), proabably in parts influenced by JRPGs back then, which provided very different experiences back then when compared to contemporary Western CRPGs. They also got rid of "downtimes" / "travel" or anything in between adventures/quests, plus you exclusively find new locations on the map solely via getting a quest. Locations that also are chock full of "points of interest", which mostly seem to serve the sole purpose of advancing the quest's story most of the time. No more houses, locations or huts in a forest / settlement forest existing because they may just do that, existing.
More recently, an experience that oft reminded me of BG1 was Kingdom Come Deliverance, in particular as to its exploration, albeit in a different first-person solo character format. I don't expect many developers to recreate a similar feel outside maybe of smaller indies, as a majority deemed that a bit borderline "boring" even back in the day apparently -- the devs of KCD were also aware of that they may "bore" players with their world design. Currently pondering about whether Wartales may also fit that bill.
RE:
Inventory management, it's funny reading about it here. But BG et all still plays tons nicer in that regard than say DOS1 ever did. In terms of inventory management DOS is absolutely painful to play, even if you don't loot everything dropping to the ground. Despite the years in between those games, the amount of clicking in DOS required is absolutely bonkers insane, even for something as simple as swapping items between characters (which in BG, is but like two clicks). Part of that is due to the optional coop, but not all of it.
But then I only found out later that people in the IE games in general would loot literally any random crap (as enemies would naturally drop everything they would carry), having to travel between looting location and the next shop over and over again because of the limited inventory space. It was pretty clear to me early on that this was done for "simulational reasons" back in the day, rather than a looting requirement for (even more) money to be had. Like, why shouldn't everybody drop what they were carrying? This was a CRPG proper, not some hack&slash Diablo clone, where frantic arcade-style looing and leveling was intended to be the core gameplay loop. Speaking of which, it was pretty refreshing for Pathfinder to introduce another layer on top of that. Whilst you have huge pockets, carry weight can still cause various nerfs, including travel speed (with time being a ressource to ponder about in general, rather than the game world freezing in an endless loop just waiting for the player to complete every single task).
Naturally also something not liked by everyone, but meh.
The IE games in general, whilst dated, play far nicer than what their age suggests in general, which in a huge part is because of their RTS influence, a general control scheme that doesn't get much more easy/intuitive on keyboard+mouse in particular -- there's a good reason why there were so many RTS clones. Go a generation of Western RPGs back, or even two (Ultima 7, 8 and the like), and the difference is striking.
