The thing about gen 5 sleep is that the sleep mechanics are so busted that the sleep status as a whole becomes really busted. No other gen has the same broken sleep mechanics. It'd take a lot of time for me to explain all of them, but I think we'd have a really unbalanced MU fishing based meta with no bans.
Other thing who annoying me is have good Pokemons with weather ability as Ninetales and politoed but I can't use it together with weather abilities.