Tigole wrote an apology for the bugs encountered in Blackwing Lair and made a logical explanation for the instance not getting tested in Public Test Servers(PTS as Tigole refers to):
I apologize for any bugs that you or your guild has encountered. It’s important for you to understand that the reason Blackwing Lair was intentionally held from the Public Test Realm was because of the repeated requests of this very community. Was that decision the right decision? At this point it is tough to say. While we have taken many jabs lately, I can say with complete faith that we did test the zone. No amount of internal testing, or PTR testing for that matter, can ever successfully replicate a live environment.
The endgame content is a very tricky beast. On the one hand, no one wants it spoiled. Due to the competitive nature of the guilds who attempt this content, they want it live at the same time, so they can all tackle it together and know that if they killed something first, they had the same chances everyone else had. Yet at the same time, this endgame hardcore community is probably the most vocal group of gamers playing WoW. While they have no problem posting things like “we’d rather not have BWL on the PTR and endure a few bugs” I question whether or not they really mean that.
When we put a dungeon like Dire Maul out, no one minds that we put it on the PTR. Everyone knows that Dire Maul will be beat the night it goes live. And the people who go to the PTR to test are usually made up of very hardcore players. So for Dire Maul, you get a very small percentage of hardcore players who have “spoiled” the dungeon yet it benefits everyone. No one complains about competitive advantage. But Blackwing Lair is targeted *solely* for the hardcore gamers. Knowing the zone is on the PTR would make most hardcore gamers and their guilds feel compelled to log into the PTR for the 1-3 weeks that the content is there to maintain their competitive edge. At the same time, they wouldn’t be progressing on their Live Realms. The content that they would be spoiling is for them… and when that content went live, it wouldn’t feel new or exciting or challenging. For example, these boards were in an uproar when Azuregos died on the Test Realm.
The decision to not put BWL on the Public Tezt Realm was done with the best intentions. I can see now that it is not true that many guilds would rather endure a bug than to have this content spoiled.
I apologize for any bugs and hope you can at least understand the dilemna that exists when it comes to testing the endgame content in World of Warcraft.