I've noticed that a lot of times, the outline and fill in does not always bond enough. This is an idea to fix that.
You can add a feature that will change the outline shell for every other layer. For example, if you set the standard outline layer count to 2 and the every other layer to 3 it will sandwich the fill in of the 2 layer with the 3 layer above and below it.
My suggestion is to be able to specify how many outline layers there should be for every other layer. If you want a stronger bond, you could set the normal outline shell = 2 and the every other outline shell = 4.
Obviously for the layer where the outline is 2 the fill in will go up to that outline layer, and the same for the layer where the outline is 4.
The fill in for the layer where the outline is 2 will be more than the fill in where the outline is 4.
000fffffff Layer 5
0fffffffffff Layer 4
000fffffff Layer 3
0ffffffffff Layer 2
000fffffff Layer 1
From the side it will look like this where O = Outline, f = fill-in.