Mire in Misery will be very hit or miss since it requires opponents to sacrifice a creature or an enchantment
Kagemaro, First to Suffer is a walking Mutilate and that's just too good for us not to run
But with a few choice upgrades, you can take Strefan from being a good Vampire tribal Commander to a scarily powerful Blood token-focused one
I can only speak selfishly, of my own experience as someone who enjoys trading card games
Plus, since it has partner, you can choose to include a secondary commander to enhance Voltron capabilities like Ardenn, Intrepid Archaeologist or Akiri, Line-Slinger
If you do, you get to flip over cards from the top of your deck until you find a nonland card