THUNDERPOW10'S PROFILE

So, there's a concept I've been tossing around in my head and I've hit a roadblock with pretty quickly. I'm attempting to make an rpg where each of the 4 characters has a distinct system integrated into their skills. Here's what I've got so far.

The melee/tank character employs a "stance" system. He'll progressively gain normal skills as well as stance skills. The stance skills will do things like change his default attack and defend moves, change normal skills, or give entirely new skills exclusive to that stance.

The mage character will use a "charges" system. This character is able to spend a turn to gain charges of certain elements, like fire and ice charges. These charges can be stacked up to a certain count, currently unknown. Once he's ready to spend them, using any "cast" spell will spend at least one and up to all of the charges for different effects.

Based on those two characters I hope you see what I'm trying to go for with the last two characters. The issue is, my mind has hit a brick wall in terms of inspiration, and so far I'm not entirely sure what the last two should be. I intend on having a speed character and a support character, but I'm currently unsure as to how their skill systems should function. I have a few ideas in my head, but I'd like to know what your take would be on unique skill systems like the ones I've detailed above. I'd also appreciate any references for inspiration that could help breaking past this block.