This is such a complex thing to discuss, it brings up the very nature of what a Pokemon battle is.
A Pokemon battle, as designed by those who made the game, takes variance, "luck", and risk/reward as components of the matches. Confusion, priority, all these things are that which, for better or for worse, help define what a Pokemon battle is.
As a competitive game, pokemon's variance is frustrating, almost juvenile in comparison to others. If Pokemon were a fighting game like street fighter, this variance could be likened to having their fighter trip in the middle of a well practiced combo due to random chance of slippage (like that idiocy employed in smash bros brawl).
If pokemon's variance were a sports game, it would be like fifa's pass assistance that purposely makes you pass to a teammate too far, or make your defender trip on their own feet as they go to intercept a CPU pass.
There's no doubt about it. As a competitive game, Pokemon is subpar. There's too many things out of a players control that greatly affect a match. In a match once, my opponent burned me with a flare blitz and critted, while my entei's sacred fire failed to burn after four back to back strikes.
As players of this game we have two choices:
Submit to the random, broken aspects of the game.
Tailor out these parts to make the game rely less and less on such variances.
Obviously the second path is the one chosen. Ok, and so far the bans have made sense. They are bans that prevent a player from winning without skill in prediction, team building, and move set choices.
I write all this because, while I think preventative measures are necessary I am a bit disappointed in the amount of players calling for the ban of all confusion moves, or for the ban of prankster, and worse, how much support they're getting.
If a player relies on confusion, you shouldn't be having trouble with them. Anyone who flips a coin and closes his eyes can be easily stopped. Grab the coin and put your winning side on his expectant, naive palms. Players like that aren't a threat.
Prankster? Low distribution and skill can be employed to defeat it, without reliance on variance. Prankster sableye? Bring in a fire type, or a cleric, or a Pokemon that can stomach a burn, or a special attacker who doesn't care.
Thundurus? Klefki? A ground or electric type sounds good to me.
The rest? Purrloin, and Murkrow? Gimme a break. That stuff is in NU and rotting for a reason.
Forgive me for be so broad and pompous, and I do agree that there needs to be a counter measure for this style of play as it is abusive of game mechanics, and requires little to no effort on the part of the player.
When does this abuse begin? When prankster allows confusion to strike first. At that point that variance rears its ugly head, and suddenly the game is a toin coss.
Confusion isn't the problem, prankster isn't the problem. Priority confusion is, because it brings back that variance the mods here try to so hard to carve out.
Ban prankster being used in conjunction with a confusion inducing move. It's complex, but its better than banning abilities and a game mechanic.
What next? Ban serene grace? Ban flinch moves?
Come on guys. There's always a cheap tactic in every game. Don't blow it out of proportions.