Agreed with the lack of foreshadowing in BG1 and BG2! While sometimes fights are foreshadowed, either by the details of the quest or the terrain (hmmm, it's a long, wide staircase with a long, wide hall at the bottom - is there a dragon at the end? Yes, yes there is), there are definitely some really tough fights without much warning about what's coming. I probably underestimate this in my own playthroughs, because I've played it enough that I know from experience what enemies each fight has, but it's definitely a lot harder for new players.