Ezuri, Renegade Leader gives the elves deck a win condition in the command zone, and some protection from board interaction
Goblin Charbelcher and Oops All Spells can utilise these new cards to cast their combo pieces that rely on the decks not having any actual land cards in them
The "single-target" clause means this doesn't work with things that target multiple creatures, such as Blasphemous Act or Delayed Blast Fireball
The universal dilemma of the Infiltrator was that few decks that played it wanted to tap out to get him there, but sticking him on the board was so devastating that most opponents would consider themselves fortunate to spend that window of opportunity making him go away as trying to race him with a traditional three- or four-drop was pure folly and playing your own blocker, including your own Shadowmage or something a little bulkier risked a removal spell that would lead into a downward spiral of card disadvantage
Still, Mono-Red Aggro has been on the heavy decline because it doesnt really beat anything now, so this negative may rarely come up
If youre buying booster packs or other physical Magic cards, I suggest hanging on to your hat until we get just a bit further down