Yes. People are boxing mythic+. While it is a bit more challenging as far as instance mechanics than in Legion, it is doable. So far the best success that I've seen has been found with trinity setups, but some are still running all tank teams, all hunters teams, and I did a +4 on a 1×Prot & 4×Ret Paladin setup. So in theory at least all the options are viable to an extent. Some fights gave mechanics that are not doable for most non-trinity setups though.