[quote=@Ioua8654]
He can override it with the hyper beam or Giga Drain
[/quote]

Giga Impact, not Giga Drain.

He's still only hitting every other turn. You're not overriding the effect, just working around it.

Slaking is hardly overpowered, especially since he can be countered by just alternating Protect/Detect with another move.