I think it would have been a better idea to have the system be as it was, with the addition of one or two out-of-the-way (that is, away from any other NPCs) banter trigger points at some location on each map. That way, you still have the natural aspect of random conversation while exploring the world, but also a way to hear everything if you need/want to.
Mine seldom triggers but when it does, it almost makes the wait worth it because of how and when it triggers. It takes on an unintentionally hilarious effect sometimes. It once triggered twice immediatley after each other after my group had slain a dragon and was looting the corpses. I suppose downtime after dragon murder and wading through its slain brood is the appropriate time for a relaxing spot of mental chess.
The best incident, however, was when a group composed of Lavellan, Solas, Sera and I think Cole was exploring this ruin full of the living corpses and demons lurking around the corners. They'd just found a pile of corpses that looked like civilian people who'd been murdered brutally while they had desperately been trying to get into a barred building but in vain. Naturally, this was the bestest of times for this bit of dialogue to trigger.
Sera: "So, you and the Lady Inquisitor. Interesting."
Solas: "Your interest is not my concern."
Sera: "That's all right, because I meant boring. The elf always takes the elf so that banging bits will mean something."
Solas: "It is not a topic for discussion."
Sera: "Oh, come on. Drop 'em and rebuild the empire. Phwoar!"
Inquisitor: (Laughter) "You're ridiculous"
Sera: Not me. It's him! And you."
Solas: "Only one of us is looking sad and foolish, Sera"
It changed the tone of the banter since it came off like Sera was trying to lighten the mood and that was the only thing she could think of to say in the moment. It had such a ridiculous timing that it became hilarious and I decided to headcanon that, that was her intent and that my Inquisitor found it just as amusing as I did because of how silly it was.
What really sold it was that this was long after the break-up had happened in the storyline. Way to be late to the party, Sera. I think even Cassandra had her banter about it a while before you did.