Duncan male warrior - strength 18 (bg system)
Alieandre female sorceress
Conversation goes:
Duncan: *Is picking up heavy axe of the ground.*
Alieandre: Is thinking *Such muscles! I must let him romance me.*

Thing is that it would add terribly much complexity into game. Because even if you are not her type there should be way for you to "seduce" her. So there would have to been three types of conversations beginings
1. She likes your body!
2. She is like "meh".
3. She finds you repulsive.
I think that writers would be on suicide watch if they should write all of this

I think that idea is good, but terrible to implement. Lets start up small. Then maybe in DoS.... erhm Divinity3.
Yeah, if you are a terrible writer. With a simple bioware style system the conversation could also start:
Aliandra: Hi, I love you because you are the hero and I'm attracted to heroes and I know you are a hero because you did that nice thing just before, and you also talk a lot with me, whichi I like heroes to do.
Duncan: Yeah, I go boom boom on baddy baddy...

(Actually Duncan is spot on for Fallout NPC)
Sure, it's more complex, but this is a video game, and what they are doing with the competitive questing is already ten times more complex than this. It's just about unlocking a dialog script, when certain critirias are met.
About the writers going kamikaze - You are talking about a company that midway through their prodution decided to make every animal in the game talk, but only if you choose one specific talent!
Edit: Fallout 1 and 2 had a lot of dialog options based on your stats. Every dialog line was rewritten I your intelligence was low. It's the same, just with the npcs saying things based on these.