It's difficult to see the whole picture by just looking at the API calls, because you're not seeing the decision trees that trigger them in the first place. There are many hours of trial and error, and sometimes performance implications, behind why these things are worded in the strange way they are.
As for your suggestion, it opens up other creative ways of misinterpretation. "Sure, I'll take the road to the capital with you later tonight." -> Clearly she agreed! -> Following you! You could add more layers of various checks to account for this kind of misinterpretation here, but at some point you have to, again, start thinking about performance. I still believe it's a decent suggestion, and I will try replacing the already existing double checks with it.
Starting at 1.6.2d, this also no longer forcibly ends the dialog, and works the same as it does when talking to multiple NPCs.