So, I know this is an old thread, and I don't mean to necro but; I would like to +1 this layer-grouping request... It would be so nice to put all my layers in a group and collapse and/or hide the group, or move multiple layers at the same time by just moving the layer group.
Basically; for some characters I do I like to put my body on one layer, left hand on another, right hand on another, head on another, hair on another layer, etc...etc.. this way in the game I can separate them out as separate objects. Did they equip a helmet? Hide their hair. Are they walking to the right? Draw left hand first. Are they walking to the left? Draw right hand first. Not only that but if I just want them to move their hands for example; I don't have to draw/copy-paste 3 new bodies, heads, etc for every frame of the animation... I can just move their hands and if I want to give them a fat or muscular body; I just swap out the body and the head/hands can stay the same.
I also like to draw all my art for one project in the same file... This way it is easier for me to color coordinate and plan animations that interact with each other (such as riding animations)
As you can imagine; I end up with a metric xxxx ton of layers. To say that sorting through them all is a hassle; would be an understatement and it would be nice to abstract groups of layers away (for instance; all the layers that create a horse) into a layer group.
This isn't a knock against the product. It is a wonderful product and obviously; there is a good reason I use it over other tools but; layer groups would definitely make my life a lot easier.