I think Garchomp should be tested with sand veil. With rain more common than ever sand veil isn't nearly as broken. Sand was the only autoweather in gen 4 OU (besides rarely seen hail) so there was nothing to stop sand veil once Tar or Hippo were sent out.
Sub+SD is the set that most abused sand veil, but that leave chomp only 2 attacks, (EQ and outrage). Gen5 gave a power boost to all multi-hit moves. Icicle spear from scarfed mamoswine, or cloyster will break garchomp's sub, and KO.
Gen5 has other checks to chomp that gen4 didn't.
(04:26:54) TryHardJobriq: why isn't kyurem-B faster than kyurem-W?(04:28:16) The Gr8 Mighty Doom: the chains on his legs are slowin him down
%jobriq: :D <==I was driver for 5 seconds
chaos: if im timestalled i go super saiyan