The Halion heroic 25 fight is just the right mix of difficulty without being too bad. My major beef with it is the huge hit box and hunters minimum range to dps, which kills my dps on that fight. The adds up top really make it a much different and more difficult fight. The twilight cutters in the shadow realm are pretty easy to deal with once you get used to it.
Heroic LK, on the other hand, crosses the line. It's so unforgiving.
P1:
- Avoid void zones (instant death) while staying close enough to the drudge to drop off plague
- Drop plague off on drudge
- Tranq shot on enrage (my job, and it gets super fun if there are two up at once)
Transition:
- Continue to tranq shot the drudge until it's dead
- Misdirect the enraged spirit to the tank (knowing the status of drudge so you don't put the spirit on the add tank until the drudge is dead, or the LK tank right before P2)
- Manage pet so that it doesn't stick on Lich King and waste its dps
- DPS down orbs (my job)
P2:
- Drop frost trap on boss for valks
- Position defile out of the path of valk
- DPS valk to 50% before it drops your homie off the cliff
Transition:
- Same as before, more orbs (yay!)
- Enraged spirits spawn so fast you can't reliably misdirect
P3 (this is the most fun):
- Gather on main tank in the shadowmourne room. Stick on him like glue while he takes the raid around the room avoiding wicked spirits.
- Somehow target and DPS down the spirits when you stop, and/or jump/turn and attack while running
- When pop back up top, immediately drop a frost trap in the middle of the room and have a tank drag LK through it to slow down spirits. Have another tank burn a cooldown and explode all of the spirits at once.
- Manage location of defile
- After the next round, have a different tank or someone with a cooldown explode the spirits
And do all of that while dps'ing down a boss with 30 million hp's in 10-man