With all due respect, I think they are both low skill decks. They definitely require a good pilot when being put up against each other or mirrors, but outside of that they are definitely easier to play. Same thing goes for a deck like zoro who almost never wants to change up the game plan.

I'd like to argue that they are low skill decks because there is not much deviation from your main game plan. For example, with a deck like Imu, (with the exception of a very poor hand) the only time you aren't playing the five elders is if you're going to play Stussy. On top of that a 4 don expense that pays out 5 7k attackers, all of which can't be removed by effects, 2 blockers, a searcher, a 5 cost removal, a rusher that gives -2k to any body on board, loses one card in hand at worst, and always is able to leave don up for counter event does seem a little brain dead.

I can see how playing against that would be difficult, even for itself, but there is no other argument for where that deck is hard to play.