What people forget is that Thragtusk was a staple in Standard before getting reprinted in so, so many sets ( Explorers of Ixalan, Jumpstart, Double Master, Modern Masters 2017, Time Spiral Remastered, a Secret Lair, and now New Capenna Commander)
In a dedicated mill deck, that -2 ability is going to be great
Don't be afraid to take out cards that are typically good but are poorly positioned in the current game
Sanctifier En-Vec This looks to be a flexible sideboard card as it hoses dredge and also incidentally hits Deaths Shadow, Prowess and Burn with its protection from red and black
Some popular Commanders that are particularly adept at abusing Cloud Cover are Tameshi, Reality Architect, and Brago, King Eternal