Matt, I like him.
But there is a bit of a bet that seems to be played by the M's that he's more than just "some level of usable."
I'm about 100% convinced that he's "some level of usable." Already he's a decent 4th OF, bench guy....precisely because he doesn't have huge holes, as you mention. But whether he is a reliable RF bat, which usually asks for some thunder, is a different thing. Jason Heyward was some level of usable last season...heck, he won a GG. But his 70 OPS+ doesn't get him anywhere above that level. At 110-115 he was a tremendous MLB ballplayer.
If Haniger hit only .220, but with 24 HR's and a 90 OPS+, I would think he was fine and dandy, as those HR's would drive in some runs.
Three glovey 85 OPS OF's is not a real recipe for success. Or at least it is hard to find teams that used such a recipe.
Were Haniger in CF, I would be much more lusty about him and about our chances, because it would likely mean a more booming bat in RF.
Steven Souza is a pretty good MLB player. If Haniger gets to 100 OPS+ then you can bet I'll be a happy camper.