Dont think they should be used anyway because for example a garchomp could just use sub and hope for a miss then set up swords dance with his mega form and sweep. They could even just use sand storm themselves to keep sand veil going. So even though weather is harder to keep up, its still not a good enough reason to let the abilities be used.
Except that banning them is stupid and pointless. Who cares if Garchomp is trying to fish for a miss? 9 times out of ten that's just going to lead to a KO'd Garchomp. It's a bad strategy that will only get the occasional lucky win, and ladders and rankings are obviously able to handle the occasional lucky win.




