Blue's milling tends to come in two mechanical parts: spells that mill numerous cards once, and permanents, most often creatures, that can repeatedly mill smaller amounts of cards
Moreover, ETB creatures tend to work best in midrange and control strategies that grind out value rather than aggro decks which win before card advantage can take over
The card feels somewhat winmore and its not unreasonable for the table to throw removal towards it because it will draw you 6 cards per turn rotation in a 4-player EDH pod if everyone takes a regular turn without drawing extra cards themselves
If the permanent is an illegal target by the time Chaos Warp tries to resolve, it won't resolve and none of its effects will occur
Did you catch all the symbols dancing in the art
And then theres aristocrat decks, which are all about sacrificing your own creatures