@Brass-Man Well, if you want to play blue for some reason, you should probably have Tinker and maybe some cards that care about your artifacts like Thoughtcast or Reverse Engineer. Mishra's Workshop is still one of (the best?) cards you can play in the format; so I don't see why you wouldn't be playing it outside of some janky combo deck. It's the most consistent, best deck, has always been, and always will be.
With people looking to fill open slots in their deck, I think we already have the perfect answer. I can only imagine that shops (and probably oath) will increase in popularity, and Spell Snare neatly answers most of their deck for the low, low price of U.
Spell Snare sees a lot of play in other formats, and I've been surprised by the lack of play in vintage. Maybe I'm crazy, but I think it's time for the little guy to shine.
@garbageaggro I see all of your points here, but the alternative is running a 3 mana sorcery that's more likely going to cost 4 or even 5 when Bob is not taxed by Thorn. Bob ONLY loses to Walking Ballista against shops; Painful Truths loses to their entire deck.
I already got Andy's opinion on Dark Confidant, but I am appalled by the lack of Bob in this thread. I've played many games with it in a similar deck, and I would not even think about playing Painful Truths especially in this format where no one plays removal (no, 4 Swords is not "removal").
You definitely want to practice against Shops (something like this), Mentor (here), Oath (something like this but it could be different creatures/no Saheeli), PO storm, and that's about it. Shops and Mentor are basically the entire metagame according to both MTGGoldfish and mtgtop8, so you definitely need to have a chance against both if you want to have a successful deck.
Grafdigger's Cage is a popular sideboard card since it helps against both Oath and Dredge (not super common but a deck that is played), but many Oath lists are just running castable creatures; so they don't even need to use Oath to win. Outside of that, it really depends on your deck, your colors, and what the meta says.
@Smmenen The first point of your post is exactly why I moved away from Eldrazi Temple/Ancient Tomb and basically went mono white. The mana in that deck can be an absolute nightmare at times, and I've been much happier with my matches since. You do lose out on a few more explosive turns and TKS, but I never even tried Reality Smasher since I didn't think what basically amounts to a dragon is good enough for this format. That's obviously not to say that it isn't as it's won many games including against me, but I'm not sold on the 5/5 trample haste for 5 in a world where you can just die to Tendrils.
I definitely think the deck is strong; but like you said, it really limits what you can include in your deck both mainboard and sideboard. Thankfully, due to the recent upswing in popularity for Fragmentize, I don't think playing Null Rod over Stony Silence is really a liability at this point (assuming that's a card you want to play- and I think it is).