OPEN 5v5 is closer to “true” 6v6 because you can create better synergies, have a higher skill pool and skill ceiling because of the combinatorics involved in solving multiple win conditions.
OPEN is just better on paper. In practice, the koreans know this (more popular mode there), and they’re the best players in the world. It’s only the NA streamers, their fanbois, and weekend casuals that want to be spoonfed some kind of lower barrier to entry structure. OWL was a scapegoat. With OWL ded there is no reason not to tune/balance for an OPEN or SEMI-OPEN format (like “too many x”). It’s more futureproof (faster queues and more DoF for fun).