Its generally expected that any future unbans become a Game Changer as theyre unbanned, and future bans are likely to be added to the Game Changer list first
Mystical Tutor, Enlightened Tutor and Gamble all fall under the limit, and if you've got your Leyline of Anticipation or Vedalken Orrery on the field, you can even mutate Vadrok at instant speed and throw any of a number of counterspells onto the stack
We can always reban it if it ends up being a problem, but odds are that it would be perfectly fine in the format
However, in competitive formats like Modern or Legacy, there are more efficient and powerful options like Ral, Storm Conduit or Teferi, Time Raveler that may overshadow Ral, Crackling Wit, making it less likely to see play in those environments
If multiple creatures enter the battlefield at one time, this ability triggers once for each of those creatures
If Purple is both the new, exciting thing and the most powerful thing, then that could lead to an overabundance of purple decks and could cause severe damage to Competitive Magic