It so happens that four of my colleagues own BG2 -- yet none of them managed to get past the beginning of Chapter 2 in it, let alone finish the game. These are all veteran RPG'ers -- both PnP and computer, not casuals raised on console games. You know, folks who have played through most Might & Magics, Wizardries, Ultimas, Fallouts, and so on. And, would you believe it, there are regulars right here on RPGWatch who never managed to get into BG2 either.
As for me, it took me a dozen tries and thirty hours, and plenty of encouragement from here, to get past the game's gameplay problems so I could actually get down to enjoying it. I did finally get there.