It would be nice, yes, but unfortunately it's not that simple. There are two immediate stumbling blocks:

Firstly: for those of us with the el cheapo LT/NV version of Keyhole (and that's most of us), it's only possible to view one overlay at a time.

Secondly: Pro users can switch on multiple overlays. And while this is nice for flying from place to place on autopilot (tracking the path of a hurricane, for example), what I think you're getting at is the ability to view a timelapse movie of, say, the last half-hour's rainfall over the Bay Area. This means viewing the same patch of ground, so simply switching on all your overlays is going to create a nasty Picasso effect.

There is a solution, though. With various scripting doohickies, it's possible to feed dynamic image URLs to Keyhole. Check the attachment if you'd like to see a timelapse of my local NEXRAD doppler radar over the last half hour.

(You may have to double-click the folder to force Keyhole to fly to the location. There are five images, changing every ten seconds.)

I'm working on expanding this. But ... I'm a hundred pages into a hundred books, y'know?