I tested the changes on the PTR last week. 57K dps although I was just using a dps "rotation" without Xuen, including our T2 talents and without Renewing Mist so it would've fallen off a bit.
As for your Ilvl: 48x is sufficient for doing some Ulduar10 hardmodes. TBC raid content should be soloable (except for Brutallus. You'll need a decent MW kit to survive his hard hits) as Windwalker and Naxxramas, OS10 and TotC10 should be doable as well as most of the fights in ICC10.
I use Dampen Harm or Diffuse Magic instead depending on the encounter and the damage done there.I get a lot of my healing from Healing Elixirs aswell, and it's getting buffed in 5.2 (iirc) so suppose it will all balance out.
Brutallus and Sindragosa are good examples for Diffuse Magic. Bosses that take time to kill due to mechanics such as Lady Vashj in SSC are easier with Diffuse Magic than Healing Elixirs. Atleast that's my opinion.