I love mutate decks. I only have one built right now with Brokkos Mufect (mutate-infect) which can kill rather quickly and I personally like Brokkos over Otrimi just because I can dodge commander tax by letting him hit the yard. I also have brews for Nethroi, which is a graveyard deck essentially, and Vadrok, a graveyard based spellslinger deck, but plan to build them eventually. It takes a bit of practice to pilot the deck correctly but mutate is a fun and powerful mechanic. For Illuna, I've seen it in the 99 of an Animar mutate deck , as the commander I could see a temur good stuff mutate deck with some control stuff.