but if there isn't a card there that is a great play for you, you're still taking things away from the other player. and most decks aren't going to be super heavyy on things that are BAD to cast. Take their Hollow One, it denies them that resource, and if you get a single discard discount or even if you pay the full cmc, a threat light control deck won't turn down a 4/4 when you have mana and nothing much to do with it, right?
1. This is the same trap that Mill aficionados fall into. Since none of the 3 cards go back on top of the library, you aren't leaving them to draw bad cards and so you effectively aren't denying any resources. The top of the library is in effect no different than the bottom if you aren't able to manipulate their draws. (There are niche cases where this isn't true, like if they make bad decisions with a Serum Visions or Jace Brainstorm, but there are also cases where putting things in their graveyard is also advantageous for them, so I'd call it a wash.)
2. I will never argue against getting another resource, but since we're comparing Thief to Shadowmage Infiltrator, we're talking about the difference between drawing from a deck built around someone else's synergies, and drawing from your own, where every card presumably contributes to your gameplan. If you're playing a control/midrange mirror, Thief is probably better by merit of his selection, but against the rest of the format, you probably would rather stick with your own cards.
Plus we're still talking about a 3-mana 2/2 in Modern without an ETB effect or built-in protection/resiliency. The closest thing to that which sees any play is Magus of the Moon, which just turns decks off when he hits the board.
Quoted for truth - I nearly wrote entirely the same thing. The psychological implications of being milled is a very, very real phenomenon. In my commander group, a mill effect (or sometimes even something like a wheel effect) draws the ire of a couple players in this group. People don't realize that their deck is a resource, just like life, and it only matters when that resource is 0 - and in the absence of tutor/selection effects, the card at the top of your deck is no different from the bottom card. Furthermore, you can use your opponent's mill effects to give you information regarding the probabilities of your next draws. If your opponent milled 2 wrath of gods from your deck, you may choose to play your creatures, knowing that you have less reason to hold them in hand for a 1 sided wrath followed by a quick recovery. What occurs however, is when that mill hits a solution/game-winning card, the milled player feels that the "millstone won the game", but when it hits two blanks (land, land), they don't have the feeling the millstone lost the game for their opponent.
I love this card (hate the artwork, but whatever), but in the standard we have seen lately, we need more value/resiliency at 3 mana. I also feel that comparisons to Gonti are flawed - guaranteed vs potential value, and that gonti was a (mediocre) answer to things like carnage titan. It will be fairly bomby in limited, but so will 3 dozen other rares and mythics.
Quoted for truth - I nearly wrote entirely the same thing. The psychological implications of being milled is a very, very real phenomenon. In my commander group, a mill effect (or sometimes even something like a wheel effect) draws the ire of a couple players in this group. People don't realize that their deck is a resource, just like life, and it only matters when that resource is 0 - and in the absence of tutor/selection effects, the card at the top of your deck is no different from the bottom card. Furthermore, you can use your opponent's mill effects to give you information regarding the probabilities of your next draws. If your opponent milled 2 wrath of gods from your deck, you may choose to play your creatures, knowing that you have less reason to hold them in hand for a 1 sided wrath followed by a quick recovery. What occurs however, is when that mill hits a solution/game-winning card, the milled player feels that the "millstone won the game", but when it hits two blanks (land, land), they don't have the feeling the millstone lost the game for their opponent.
I love this card (hate the artwork, but whatever), but in the standard we have seen lately, we need more value/resiliency at 3 mana. I also feel that comparisons to Gonti are flawed - guaranteed vs potential value, and that gonti was a (mediocre) answer to things like carnage titan. It will be fairly bomby in limited, but so will 3 dozen other rares and mythics.