Mages often sit at the highest win rates in the game. In high level play, Bloat, Nefara, and Slith are all considered absolutely devastating as mages, bloat due to his gauranteed 1.5 second charm on an enemy sniper leading to a guranteed kill . Slith's damage is easily the highest of any caster, and he will win duels against anyone late game due to the reliablility of his stun and how much dmg he just puts out with reliable accuracy. Nefara is the games most obnoxious CC mage. Having Silence, Blind, Root, Pulls, displacement, knock back, slows. She has the most potenttial CC out of any commander in the game, albiet also the highest skill cap.
Mages aren't weak. Neither are tanks. In low level play, AD AA's and AD brawlers are more popular since they are easier to snowball and carry with. My suggestion, Armor pen and raw Power will do insane burst dmg with casters. Try slith. He is the easiest, and most powerful caster to play for newcomers. If you have chances to kite endlessly, Eos and Nefara using Caster Sustain with Energy REcycle, followed by Entropy for CDR, wil lbe able to throw out spells every 2-4 seconds, heal while casting spells, and kite endlessly. Both also have tools to help them escape, making these poke builds obnoxiously devastating the longer the fight goes on.