Bumping this. Seems like a pretty simple thing to impliment and would help with all those drawings that are more diagramatic or illustrative - which have to sit over the live model.
This change would create more consistency and open up other possibilities. It would be possible to have separate Filled Region Schedules where you could schedule the Area parameter. Additionally, if you have a Filled Region Tag, you could tag the Area. We need to use way too many workarounds now to achieve this.