Well, if you could stomach Aerie's early dialogue, you have a pretty fun relationship with her in Baldur's Gate II. A few rolls in the sack, a baby quarter bhaalspawn, just like you would expect. She gets fiesty later on too! Back to the topic though...
Emotions are really the only way the writers can touch the player. Once my character heard Aerie was with child, he made damn sure he didnt need to use any rods of resurrection. Not even the priestess of Bhaal couldnt get past my Warrior. The way Aerie developed was what made that character fun. She started off as a sniveling coward but she really came into her own and gained faith in her abilities.
For a change of pace, Id like to see a romance that involved a strong woman. Im not talkin Amazon queen or anything, I mean very set in her ways. Stubborn, independant, etc.