How about a user-adjustable control in a menu somewhere of the zoom level at which the switch between the available maps (WAC, sectional, TAC, etc) occurs?
I find that the switch to TAC from sectional occurs several zoom levels in from where I'd like to see it and the "forced" option switch is clumsy.
Living in a TAC area, I am zooming in and out constantly during a flight - but I don't want to zoom down to the pedestrian-level just to pick up a visual waypoint that isn't on the sectional.