The reason why I don't find Dragon Age to be quite at the level of BG2 in terms of combat is the weaker spell system. In Baldur's Gate the spell system was very versatile and you had to adapt your spell selection according to the opponent you were facing, but in Dragon Age you are forced to work with what spells you have selected, which really reduces tactical possibilities. For example I've largely specced Morrigan as a damage dealer, which means that she can't really provide me with buffs when I'd need to fight a dragon.