oh boy, you can't really compare normal runs to heroics. at 81, stonecore is fun, BRC is a little ugly at times, but it's ultimately fun with a few blue items equipped. you can burn through bosses with their weakened mechanics.

10 man marrowgar, without the ICC buff, is on par with a 5-man heroic boss you'd find in cataclysm. if you miss an interrupt 2 or 3 minutes into the fight, the group will die, and have to run back. again. and again. and again. and again. the mechanic that causes the healer to OOM and the group to wipe, in a normal version, will wipe the group within seconds in heroics.

e.g. i went into a guild run of deadmines, it took 1 1/2 hours. shadowfang keep, under an hour. then, after that success, decided to reroll and got grim batol, it took 2 1/2 hours and some hilarious mistakes later. Even with ~340 and ~350 geared players, who have done it before, there's just way too much reliance on snares, interrupts and root/fears that you just won't have.

a guild member in the first week of cataclysm, spent 5 hours in heroic throne of tides, having to swap out 40 players along the way. that's not heroic, that's brutal.

my thinking is, some heroics are based upon players with tier 11 gear, and the ilevel restrictions are simply incorrect at this point,

besides opening heroics to players who just stepped out of twilight highlands with a lucky gear drop or 4, you should have to at least gained an achievement for the normal mode first before you can queue for the heroic. that would save a lot of grief for everyone.