A lot of people don't like Multi-Attack because it makes deploying all your armies in one spot and stomping on your opponents a prevailingly powerful strategy. (Which is still true without Multi-Attack enabled, mind you...)
I find that, with the proper settings, though, multi-attack games are far, far more interesting than regular games. Wastelands and blockades are a good fit, as well as anything which restricts your ability to deploy. Local Deployments is one good option.
An easier and simpler solution I outline here:https://www.warlight.net/Forum/82395-deployment-limits-easy-new-rule-implement
I've tested it in about 50 games, and it's by far my favourite way to play Warlight. Regular games are a drag in comparison.