I like Lone Missionary way more because of the 2/1 body. It's no joke against an aggro deck; trading for a guy and nullifying a turn worth of damage is big game. It's an okay blink target, able to return via
Ojutai's Command, helps stabilize your life total (4 life takes you out of the range of most burn kills pretty often), you can set up a dumb 4 mana loop with
Phyrexian Reclamation where you net 2 life each time, and you can Alesha him back if you're really hurting for good targets. Suture Priest is okay, but it's just not as interesting with that 1/1 body. I much prefer
Zulaport Cutthroat if I'm looking for that 2nd Blood Artist effect, it's also a Human!
Missionary is not an amazing card, but it's a great roleplayer in a variety of strategies. It's exactly the kind of card I like; non-embarrassing card that will usually make it into your final 22-23 and generates solid value whenever you play it.