There was no level requirement to enter heroic instances at the start of TBC, you just had to have revered reputation with the appropriate faction. Requirement to enter raid instance was 65, and I assume it was the same for heroic instances since those used the same mechanics.Originally Posted by Minus
Don't know if the minimum level was changed at some point for TBC, but I do know for a fact that I did heroic Black Morass as level 68 holy priest (rest of the group were 2x69 and 2x70) for my very first TBC heroic instance about week and half after TBC launch. Doing heroic BM was really popular for for healing priests and druids for months because getting the key there was easiest of all factions and exalted reward was epic cloth +healing bracers. Also BM dropped quite many nice spellpower items for shadow/balance offspecs.
You could get keyed to CoT faction in one afternoon easily. Run OH once in normal (minimum level 66), run BM once in normal and you're at 5/12k honored for completing the storyline. Then half-dozen normal mode instances of either OH or BM to ding revered for the key. OH was nearly impossible to do in the original tuning, requiring 1.5 tanks and 1.5 healers and 2 CC and 20-30 wipes in the first half. Real killer was patrols on 5min respawn timer (all would pop back after each wipe) and the limited attempts (3) during second half or Thrall would die permanently. BM on the other hand was totally doable even as lv68 healer kitted in all possible normal mode blue gear if you were prepared to chug down 10-20 mana potions during the instance.