If I could play Malzahar in DOTA instead of League, I would immediately be a top tier ganker and mid-laner and easily over 4000 MMR using smoke ganks. Immobile champions controlling large zones are nothing new in DOTA but champions are rarely given strong and self-sustaining waveclear or scaling max HP damage due to how defenses scale in DOTA to be more effective but have fewer reasonable items to buy.
Your argument is invalid, League's /champions/ are better than DOTA (until DOTA actually makes scaling burst mages on par and interchangeable with ADC's) but the skills and item actives are scaled back to be less impactful to try to make what's going on easy to interpret by a casual spectator or new player... something entirely unnecessary as DOTA has proven.
There are other differences between the two games and the types of decision-making or rules for sportsmanship that, if one of the games iterated on the other's ideas without copying them, would finally make one or the other the de-facto champion of ESports for the next 10 years, but both are scared shitless of crossing certain lines in the sand that the other has set.
Neither is definitively better than the other, because they are built on a severely flawed and damaged ruleset to begin with, namely that you win more games based off the enemy team's mistakes than you do your own strategy going in, and a mechanically bad player saddles a team down far more than a mechanically good player can carry it.