One card? More like one deck, this is insane in (Historic)Dimir Rogues, pretty much every single dork they play has a milling effect attached to it, also let's not forget that Mono-U will be getting this AND Brainstorm on top, tempo decks are getting quite a boost with this card, and I'm definitely not complaining.
Back in the day...I used to play this with foreshadow for a ghetto 2 part dismiss.] Anyways, while playing with that in a format with ophidian, it was far more important to draw lands instead of spells to win the counter wars. It actually was better to do a mini stunted growth by denying your opponent a chance to draw a land - instead having to draw the spell they just tried to cast - this was a time walk. Truly one of my favorite counterspells ever.
Anyone who has started playing recently might not realize how good/obnoxious this card is to play with/against. You know the sinking feeling when you're playing green or red cards and your opponent goes back to back Aether Gust against you? Well now they can play up to 8 copies of that effect against you.
damn.... WotC printed all the new stuff to historic as rares or higher on this.
getting the wildcards for all the beef in arena will be the biggest pain in the ass.
It depends on how much you draft, as far as I know, MA cards have all the same rarity, and they have a dedicated slot in boosters, they made all Standard-legal cards "uncommon" so people would know they can use those in their Standard decks but not the "rares" or "mythic".
Else, you're right, it sounds pretty aggravating having to spend rare WCs to get Brainstorms or Mana Tithes.