Originally Posted by
Elbob
In a earlier post you said you only wanted to go as hard as M+ probably so I'm going off that. My top suggestion is you play what you enjoy the most (blah blah default answer I know) but if you actually enjoy both DK and Monk and only intend to do 5 mans, you will probably have more success with DK because of how their kits are designed. Monks tanking style favors damage smoothing over damage mitigation compared to other tanks and provides almost no sustain(as you have seen from your own play). This requires healers to be much more active when it comes to healing during all those tough trash packs in M+. DK however brings a ton of sustain and moderate mitigation compared to other tanks, allowing them to be mostly self sufficient in M+.
Edit: the damage smoothing component of monk is what makes them such gods in raid. In progression raiding (mythic when you don't overgear it) the most threatening mechanic from most bosses is just plain old auto attacks. Its quite common for bosses to 2-3 shot a tank without any type of additional damage reduction up. Monks, druids and dks are blessed with 100% AM uptime making it extremely unlikely they get "popped" randomly during boss encounters.