Yea just ghosts and Moltres, Slowbro, Uxie, Mesprit, Scyther, Venusaur, and other Heracross.
Banedon has mentioned Moltres, Moltres only revenges.
Slowbro: On the switch CC does
18% - 21.3%. If Slowbro is your only safe switch into to Heracross next time you won't be happy when you see a Megahorn that does
72.1% - 85.3% Asumming you are lucky and get minimum damage you might be able to live on the second switch in...oh wait Heracross outspeeds.
Uxie: Similar scenario as Slowbro. Close Combat on the switch deals
17.8% - 20.9%. Megahorn then deals
71.2% - 83.6% which means Uxie can't do much.
Mesprit: Against the supporting attacker set which seems to have the bulkiest EV spread Close Combat does
27.5% - 32.4% , as well as ohko with Megahorn always.
The same scenario follows for all the rest. I'm not saying that the Pokemon you listed aren't safe switch in's to Heracross's Close Combat (for the most part, moltres isn't all that reliable.), but that Heracross can effecitively deal with one or more of these counters alone, but it's even easier with stealth rock support. The Dual-Stab combanation of Fighting + Bug makes the only 100% reliable switch in to Heracross, Ghosts types. That is only speaking for the scarf set as well. Imagine if someone switches an Uxie into a Close Combat and finds themselves facing a Megahorn the next turn. This means teams need to be prepared to face the versatality of Heracross in this tier.
It may just be my opinion, but if someone is going to have to run multiple mons to take make sure Heracross isn't a threat than that, to me, is over centralizing and a sure sign of a Pokemon being broken. By no means am I against testing, I want to see how it actually fares in the metagame instead of making assumptions, I am just expressing my opinion that it is going to be broken from what I see right now.
EDIT: I say 100% reliable because they have no chance of getting screwed on bad predic.