Invisible Stalker is what I need to have to put Ethereal Armor on, spirits are great but they wont have hexproof unless there are two Drogskol Captains out, I know Invisible Stalker seems out of place but because he is not blockable he gets around opponents flyers and since he has immediate hexproof he cant be removed without a board wipe. It works out really well because opponents are forced to use their removal on Drogskol Captain, Mindshrieker, etc. It works, it helps play around protection too because the people I play with use creatures with Pro-white or Pro-Creatures. It really helps win the race. Having more spirits would be great all at once but they can be blocked by other flyers.
I've considered building something like this more than once. I like it. Invisible Stalker is an auto-include in this deck because hexproof and unblockable make him the best creature to put the pants on...only way to get rid of him is with a sweeper.