Heroics OK?

I was looking for a group to do the daily heroic quest (Old Kingdon) to get the last two badges to buy my tier 9 gloves, and found a group who were farming heroic dungeon achievements. We got the achievements from the first, third and last bosses in Old Kingdom, and it was a really fun evening - much more fun than I've had in a heroic dungeon for ages.

The achievement for Elder Nadox (the first boss) in particular was very satisfying http://www.wowhead.com/?achievement=2038. The boss spawns an add every 30 seconds or so, and if the add is within 100 yards of the boss, then the boss is immune to damage. The achievement requires you to leave all the adds alive however. We eventually dealt with it by using a dps-specced DK to tank the boss, and kite him into another room. I stayed in the boss's room in blocking gear, and picked up the adds when they spawned. With my array of stuns and self-heals I didn't need the healer to heal me at all, and was on about 85% health when the boss died.

The achievement for Jedoga Shadowseeker was more trivial http://www.wowhead.com/?achievement=2056. Every so often she becomes unattackable and one of her worshippers tries to sacrifice himself to give her a massive damage buff. Normally one would kill these before they complete the ritual, but the achievement requires you to leave them alive. When buffed her melee swings hit me for 12k, while the whirlwind hit me for 20k (and amusingly one-shotted our dps DK twice - we battle rezzed him halfway through the event). There are three enraged phases - shield wall the first time, disarm the second time, last stand the third. Easy.

The final boss achievement was a zerg http://www.wowhead.com/?achievement=1862. The boss periodically casts insanity - I believe at 66% and 33% - requiring you to fight evil versions of your group members. We attempted to get him to 33% before he'd finished casting insanity, and did so first time. This meant we only had one insane phase to deal with, and we downed the boss in 90 seconds. We used our DK's army of the dead to tank him, and I went fury for the occasion.

It was a real feeling of, well, achievement and it was interesting to do the same old fights in a new way. I wonder whether it's worth going for the proto-drake mount you get for doing every heroic achievement - I have about three-quarters of them already and it would add a certain amount of interest to heroic dungeon runs.