Dromoka will have to content herself with ruling through her Commands, as she strikes me as more of a sideboard card than a main-deck one. Being immune to counterspells and making your opponent unable to cast them is not relevant in enough matchups that you need to start out with Dromoka in your deck. In decks like this, she does have some sideboard potential, but overall I'll settle for playing her Command instead.
This is the same GW Devotion deck that has been very successful recently, and the addition of
Dromoka's Command is a big deal.
Dromoka's Command kills enchantments (such as opposing Masteries), stops burn spells, and gives the deck a flexible and powerful way to kill creatures.
Den Protector is another good addition, and I'll keep playing what some have called "Maternal Witness" (a nice little
Eternal Witness callback) until she proves herself to be too slow.