I don't agree that Humility isn't problematic as a card, but I haven't seen evidence that it's widely played. And while a painful card it's not the end of the world, as the deck can still get there with equipment/Elspeth (or other planeswalkers; incidentally I wonder why I haven't seen a list of Punishing Maverick running Ajani Vengeant.)
Regardless, given the deck's other needs I don't feel compelled to run either Grip or O-Ring in my board, although I would lean towards the latter if anything. Against Blade Control I think Jace is a much bigger problem than Batterskull.
I do want to say that Silhana Ledgewalker is sweet as fuck and should definitely be in the lists running 5+ equipment slots (including SFM). In such a list it seems much stronger than a singleton Thrun, since the first ability doesn't show up when you have to GSZ for five mana and you get it Dazed, whereas Ledgewalker's evasion and much lower casting cost are pretty much always relevant.
But it'd probably be better (and here I'm going to flip people out) in such a list to cut Moms entirely so you can fit in both a double Thrun and a Ledgewalker or two. They'll give the removal-heavy decks a much more consistent headache than Mom, who can't be tutored for and doesn't do anything much past turn 1-2 in my experience, and can still fall victim to Lavamancer, Jitte or Snapcaster tricks pretty easily. Mother of Runes was always, in my opinion, a borderline card- I tested it a fair bit and always found it serviceable but underwhelming- and I think the meta is generally able to handle it at this point.
Double-Ooze is sweet and surprisingly relevant against a large number of decks; but I've already gone over my preference for running doubles of all the highly flexible GSZ targets and no singletons of the more dependent ones (Ledgewalker being an example of a creature that's really good if you can get equipment very reliably but not otherwise.)
@Majikal: Drawing double Library sucks, but that's one dead card you're drawing versus all the lands/fluff you're going to draw in an attrition war if you don't have a way to stack your deck; and games against other goodstuff decks, Zoo, Blade Control and Merfolk/Goblins usually come down to an attrition war. Library also has a high chance of being countered or killed in my experience. I really think that 3x library manipulation is the minimum people should be running, either 3 Library or 1 Top 2 Library.
I mean Library can more or less be viewed as a legendary card, and while legendary is a real drawback (I've sat around with double Jitte in hand too), it has a finite negative value. I only run one Karakas because the marginal benefit of having a second copy to draw raw against Reanimator/SnT isn't worth the cost of drawing it when I really need another land and have the first in play. On the other hand, if the card is exceptionally powerful in a wide range of matchups as Thrun or Jitte or Elspeth, then it can be worth it, especially if they're going to try and deal with that card. I know that if Knight of the Reliquary was legendary, for instance, it would certainly not be correct to only run one (might go down to three, though, not sure.)