That is the point of ults. It isnt even that much of a problem on hero gauntlet. You only suck pong enough to get your ult, then switch.
It is a hell of a lot more fun, random, and stress free than getting dominated by the team that happenned to get 2 Orisas and 2 bastions in the fembot meta.
A healer who doesnt swap is no big problem, as their team is rotating around them if successful. It isnt the presence of unengaged healers that makes MH frustrating, it is the multiple tanks and healers bunkers that are unbreakable.