We already have mythic skills based off class skills but they arent specific to one class only but I see what you're saying.
Vanish was stealth mythic but with the bllind effect. It was certainly used alot when stealth used to be OP in arena and mythic proc chances are unaffected in arena.
Cyclone was basically like Whirlwind 40 hero points and taunt. Also Twister at the same time since it shows a Twister like animation.
Nova was basically a mythic form of Coat but explosive and teleport but you don't teleport.
Enigma was basically a mythic form of wizard shatter.
CosmicOrb was basically orb skill on steroids. Basically orb but hits 20 times a second instead of 10 times and 300% MH instead of 200% MH. It hits by 10 strands of 300% MH and 10 times on its own.
Earthquake mythic was based of Earthshatter.
Rockblast was based off wands and bows but shoved rocks. It used to be explosive but it isn't.
Arc is just based of reactor arc set but more powerful.
Bombard was not surprisingly based of meteor. but smaller chunks dealing less DMG but totalled up to 1000% or so MH. Not guaranteed that all would hit though. Also created DMG like expected just like earthquake and enigma.
And Finally apocalypse was its own way to summon an army of Fury's from the sky instead of equipping legend affix fury proc but it dealt MH% instead of OH% if I recall correctly or did more dmg but more summons.