I really think the changes to the armor sets are unneeded. The two defenses the staff has (that I've heard) are 'It was designed as the end-all be-all armor' and 'You can get it all in Lower Thaz'. Both of which are a bit silly.
Point one:
It might have been designed that way, but pieces were still replaced rather quickly in ToT. The staff claims to be straying from 'end-all be-all' items, but Sanctum has been called (just like Thaz and Inner Prison before it) the end-all be-all raid zone. Most players have seen a rather unsettling pattern from the SoD staff, which is, in their battle against mudflation, they CONSTANTLY go back and nerf items, claim they won't be making items like that in the future, and do it all over again, only to nerf the items yet again.
Point two:
Yes, if you're a total masochist, you CAN get all your Thaz sets from Lower Thaz. Guess what, you could also get all of your guilds Combine gems in Outer Prison. Yet, oddly, no one does that. Because it would take ridiculous amount of time. Not to mention, you don't just deal with one RNG roll, you deal with, at the bare, nearly impossible minimum, 6. 4 mobs (in different areas) for your essences, another mob for your class specific gem, and another mob for your archetype specific armor piece.
Not to mention, with 15 classes, and 4 archetypes, the odds of you getting your pieces is somewhat slim. Plus, you have 17 other people to deal with. It takes TIME to get your armor sets, and most people got their items/essences/gems from Upper Thaz, just like they got their combine gems from Inner Prison.
The points I'm trying to make are, it's disheartening to players to get 15 HP/Mana upgrades, then have them nerfed to more insignificance by turning them into 5-10 HP/Mana upgrades. It's happened quite a bit, and it's probably going to happen with Sanctum yet again, and the cycle will start all over again. The other point is, it takes a lot of time to get your Thaz armor, then get the essences, and the gem for a piece. Not to mention, you have 7 slots that you have to take all that time for, and fight 6 RNGs. A bit more time intensive then clearing a wing, killing a boss.