I know to scale down the elements we need to individually % them up. But what if on the main page we have a symbol with a few animated element. If we could % it up, then many issue would have been resolved (I think). if you check the % on width and height is turned off if you select a symbol.
The trick is to set your symbol's stage to 100% width and 100% height. Once you do that, you can adjust your instance's width/height in the properties panel when you select the symbol instance on the main stage.
Hope that helps,