The trouble with talking about the next few zones in Wrath is that they are chock-full of spoilers. Especially Dragonblight. Dragonblight is spoiler-city.
Since my last update, I've done Dragonblight, Grizzly Hills, Zul'Drak and Sholazar Basin. The rule of two levels per zone held very well. All the zones are very good, with lots of interesting quests.
I strongly recommend doing Grizzly Hills before Zul'Drak. There is a major questline in Grizzly Hills which sets up Zul'Drak.
I also felt that the rate of gaining gear upgrades was perfect. I was in mostly T4, and I was slowly replacing epics with good blues, starting at around level 74. It was a very gradual process, and felt just right to me. I didn't replace an epic with a green until Storm Peaks. (Technically, I'm also wearing green boots, but that's because I accidentally disenchanted my blue Retribution boots.)
I also did the dungeons Azjol-Nerub, Old Kingdom, Drak'Tharon, and Gundrak. They're solid dungeons. The last fight in Old Kingdom is spectacularly awesome, with an elegant and seamless use of phasing.
Phasing in general is used more and more. In particular, Dragonblight contains the first use of permanent phasing. After a quest, one area of the world is permanently changed. This is very interesting, and I'm looking forward to seeing what Blizzard does when they become comfortable with this technology.
Sacred Shield is really nice for Ret soloing. It doesn't seem to improve with Sheath of Light, but the extra crit chance on FoL means you can keep Sheathed FoLs ticking on you all the time. Sacred Shield -> Art of War -> Instant critical FoL with ticking Sheath HoT. It's very useful for soloing elites. Plus even 500 damage reduction is nothing to sneeze at in solo content.
Two more zones of questing to go, and then I'll have to figure out what to do for endgame. I also have an odd desire to go Holy and heal some instances. Retribution is fun for soloing, but it's sort of boring in instances.