You know, at this point in the game, movesets of defending Pokemon don't seem to matter so much...the really important thing is having a high enough CP to sit at or near the top of a gym. Most active players have abandoned the game. Meanwhile, most gyms are level 10, and staying that way. Now and then, someone tries to tackle one and knocks out the bottom-level defender, but then they usually give up, with the result that the gym gets trained back to level 10 but with an even higher leveled Pokemon taking the new slot. The result is that people just stop challenging all level 10 gyms, even if the Pokemon in them aren't actually all that tough.
I've been eyeing off a level 10 Mystic gym in my area that went untouched for a week. When I finally had time to tackle it this weekend, I was actually easily able to demolish the entire thing without using any Revives, because it was half-filled with Arcanines with Bulldoze! Just the fact that they all had very high CP and looked intimidating was enough to deter the few people around who still play the game, which is why it just sat there for ages. I plonked my Dragonite with Dragon Breath and Hyper Beam (technically the worst defending moveset for a Dragonite) on top of another gym a week ago, and it's still there, because hey - it's a high level Dragonite, and no-one wants to challenge the gym! It used to be difficult for me to claim more than 10 coins per day, but these days I'm usually able to get 100.