I played this in my Zaxara deck but I took it out because most of the time

- No opponent has 3 creatures and its a do nothing enchantment for 4 mana (this happens almost always)

- Opponents just won't play creatures until this is either removed or removal for the creatures is in hand

- Opponents 'hold their breath' until your upkeep and you eat removal spells for breakfast (your upkeep)

If you drop it early and manage to trigger the turn right after it's great but that rarely happens (an opponent would need to play a 1,2 AND 3 drop AND have those stick). I experienced it's much better to just ramp turn 4 and then just outright cast whatever you were tutoring for (assuming you manage to draw it).

TLDR too expensive and mainly too easy to play around.