It'd be nice to have an additional layer above the Token Layer that isn't clickable when not on it, a la the GM layer, but visible to players. This would allow simple, partially transparent tiles to become effects like fog, underwater combat, and colored light, and would allow them to affect tokens, in addition to the backgrounds, so your tokens don't stand out so heavily against the effects. For added utility, being able to adjust the transparency of the layer itself via Roll20 would be really nice, to save time adding my own transparency to tiles.
