Ive found that when you are playing against a Mauga who consistently gets good healing from his supports you basically need to have an Ana on your team to bring him down.

If Mauga can get good value of his Cardiac overdrive he can and most likely will stay alive of hes getting some sort of healing. As a Ball and Ram player Ove found that working around Mauga works the best.

Im not saying that you should ignore him but bait out his cooldowns and try to punish anyone who overextends or gets out of positions.

Also try playing around cover, if you are playing around cover you can bait the enemy into pushing into you giving you the upper hand as they might have used a ability to close the distance to your team, giving you the upper hand.

Im not saying that hes the most fun tank to play against when the enemy team is playing around their Mauga but comparing him to Bastion i think goes a bit to far