I'm all in favor of more layers. Going one step further, adding visibility to layers would be snazzy, too. For instance, I set up one map on layer A, and another map on layer (or maybe an alternate version of map A due to an explosion or something). Being able to turn layer A off and layer B on would be swell. Likewise, using one layer for hidden baddies lying in wait in ambush - instead of putting them on the GM layer, and then selecting all of them, and then moving them to the token layer, you could just turn the visibility of that layer on with one click. Much less clicky work = smoother game (especially if there are a lot of baddies).