Well, my guild has ran every heroic 5man there is to offer. Only one boss actually gave us second pause- as none of us knew what to do- the last boss of Grim Batol. Once we realized we needed to burn adds at all costs the fight was fairly simple. 3 wipes and done. I've personally ran all the heroics but stonecore and throne. I have yet to find why they would be "Hard." I can however concur that with a random pug they could become extremely difficult.
Twice now, I've had healers in our guild complain that healing is horrible. Twice now, I've had healers remark that when your group CC's every trash with as much as possible healing trash doesn't feel harder than bosses and feels like it should. In a group with my hunter, a spriest, boomkin, and shaman healer we usually throw out (for the standard 5 trash pack pull) a trap, MC, and hex if he can get it off. I throw down my CC in under 2 seconds of standing in front of the trash, the healer hex's the moment he sees my trap go up, and the priest does the same. We have a blast doing it and it goes MUCH faster than attempting to AoE crap down. Currently it's stupid trying to use AoE when you can do more damage with single target dps. I'm pretty much amp'd for raiding to start again as I do not forsee us having too much trouble with much of the regular modes.
Just remember! As long as your group moves as a cohesive team you will succeed. When you begin to think and act as a bunch of individuals put together in a group you will most likely face difficulty. This game doesn't require much skill, and the most important of that is being a team player.
15 hours ago