I think to make each combination feel a little more unique, it would be cool for each combination to have at least one top tier skill that only that combination can use. For example, let's say you have warfare and and earth, you do some sort of slam attack that has earth damage.
#1 Unique skill for each mastery combination.
mystic marsh
loud hamlet
That sounds fun.
earnest spindle
yea that sounds cool, although fissure is already kinda filling that role so i imagine warefare earth would be maybe encasing yourself in stone to become unbelievably tanky and have certain dmg modifiers applied to it
altho the main point stands, would be cool to have a unique spell to that specific combination
mystic marsh
Sure. I was just throwing out some example off the top of my head. Or maybe they could take that skill and make it the combination skill, and then make some new skill to replace that one? I dunno.