First off, I love the new direction that boss encounters have taken to make them challenging. As a healer, I hated TSO with regards to all the curing. My two favorite fights in the zone were the Yeti Trainer and the two ice golem brothers near the end. I like that the challenge of these fights is not placed solely on the healers, but engages the entire raid force to make the fight successful.
Now to my pet peev of the zone, not to be able to fight the final mob first time through. I can understand making some of the quests require multiple runs so you can offer better rewards, but in my opinion you should be able to access the final mob first time through regardless of being able to finish every quest. Atleast from my viewpoint (and I do realize the zone was not aimed at top tier raid guilds), the reason for running the zone is for the challenge of tackling new content and the one or two items that may be good from some of the final mobs (compared to what we can already obtain from hardmode mobs). In my opinion requiring a guild to run the zone 2x just to fight the final mob seems like an annoying speed bump that just impeeds progression through the zone. If the problem is an amazing reward if linked to the yeti glove quest (which as far as we can tell is what is needed to access the last mob), maybe that reward should be shifted to a different quest.
Again, I really did enjoy the zone. Please keep up the good work