The reason mongol tower rush is a must for mongol is it has no need to spend woods to build pop buildings. and their tower cost only 70 wood. so they always have plenty of woods.
And when it comes to maps that contains water, the problem becomes more complicated.
because they starts with 200 pop, they can produce fishing ships and villagers both without pop limit.
and the reason ovoo production is now problem is they do not have to think about the pop limit for the production duplication. if other faction with pop limits had ovoo, then they should have to always build pop buildings per every unit production duplication while also training villagers.