The problem with that is it still allows them to build trips with long periods of inactivity because you aren't on the clock. Pay at sign in (and I don't mean 3.5 hours early because you commuted on the first flight) and a min 6ish hour day would force highly productive trips.

IIRC, the new rest duty rules are based on duty time not just flight time. It's a good time to change the paradigm. Go back and look at your rotations, calculate how much it would be if you were paid this way vs the current way, and factor that into rates. We could sell a smaller rate increase but actually get more money, I think.