>>35603674I'd say yes, in the context it takes place in and what you have available to you resource wise it is one of the more difficult challenges. Especially since HGSS gave Miltank a fucking Lum berry, cutting off one easier approaches for tackling her.
Plenty of other things are much harder in a 1:1 comparison, but generally those happen late enough in the game that you have a huge arsenal of options to tap into. Goldenrod Gym happens so early that your options are very limited. If you are going in blind it is easy to have a team that just stands no change against Whitney without massive over leveling.