I’ll admit I wouldn’t care to see a Monster VS Monster mode. It would create a huge imbalance. Just thinking of Goliath VS Kraken right now is like thinking of the Tank VS the Mage in traditional RPGs. Likely Kraken would win by “kiting” the Goliath.
And while we here on this forum may understand that such a mode would be unbalanced, this would unfortunately be the minority. Mass people would complain and force the game into a direction it was never meant to be.
There however is a mode that would work by default. That is a 5v5 mode where 4 hunters and 1 monster team up together to take on another 4 hunter and 1 monster team. That could be interesting and may serve as an extra game mode that wouldn’t require too much attention but at this time it’s not important.