They've made a minimal improvement to block by doubling bonus block. This is a band aid (and a pretty insignificant band aid at that since it does not affect block value on the shield or base block from strength). I need to have a look at my block gear to see if it's worth me wearing more of it. The most interesting change could be to block trinkets. I have Lavanthor's Talisman, and the change is to double the active time rather than the block value bonus. I wonder if it would be worth equipping this more often - 40 seconds of 440(ish) extra BV every 2 minutes sounds pretty fine.
Major changes are needed still here though.
Major changes which I don't fully understand, but the most eyecatching change from a tanking perspective seems to be that Ardent Defender (which gives them damage reduction when taken below 35% health) can no longer be leapfrogged by a hit that does more than 35% damage. This effectively saves them from 1 massively damaging attack every 2 minutes.
Emblems of Valor and Heroism are to be removed, effectively allowing all level 80s the chance to grab some T8.5 by doing heroics.
I don't like this change at all, but I guess I'll be right there with them since I only raid Ulduar 10 at the moment. The tiered emblem system worked very well, and led you naturally through the content - Heroics/Naxx/Ulduar. Hey ho - perhaps I'm just jealous that other people will get gear essentially for free which is better than the gear I have worked so hard to get. I suppose that when 3.2 hits I will go to the new instance, and get emblems of triumph instead. Which leads me to:
The new raid instance
What? An arena instance? You have to be kidding me. We've had two beautiful, lore-rich, atmospheric instances and now we are reduced to an arena instance. Sure maybe the fights will be fun, but please please don't try to pretend that there'll be anything epic at all about this. It's so depressingly mundane.
Ulduar has been such a success on every level - could they not have copied that? There was so much scope for an Azjol- Nerub instance, or even something in Zul'Drak. Either of those could have been filled with dramatic set pieces and could have been a really interesting location, but instead we end up with an arena. Were their artwork guys on holiday or something?
There is lots of other stuff in the patch and most of that is good - another DK nerf, PvP changes (no more 2v2 woo hoo!), the new BG, another prot warrior dps buff, mount improvements. It's all overshadowed by the bad stuff unfortunately.