I was wondering if its possible to change gap closers from skills to function with block+sprint like in skyrim? I believe its possible and would free up a skill slot for 2 hand and shield users and allow an additional skill to be added. I also believe that staffs can have a move that pushes them back from their opponent leaving a trail of elemental aoe (ive seen a certain boss enemy use this but i forget which dungeon) as staves are primarily ranged weapons this would be a neat way to avoid your enemy.
To account for cost i think the skill should not have a set cost instead cost a percent much like dodge rolling does.