As I discussed in Multistrike and You, two new secondary stats are being added in Warlords of Draenor. The second and somewhat simpler of these is Readiness. As always, anything may change between now and release.
If you keep up with World of Warcraft news, you're probably already aware that some secondary stat changes are coming in Warlords of Draenor. Hit and Expertise are being removed, to be replaced by (at the time of this writing) Multistrike and Readiness.
The TheoryCraft-o-Matic Lite has been updated with 5.4 spell data. Frost spells that generate Icicles are now listed twice, once with their direct damage, and once with the total damage they generate, including Icicle. Fire spells that generate Ignite are now listed the same way, rather than simply rolling the Ignite damage into the total. Please let me know if you spot any problems!
I've been running some Frost simulations to estimate the effect of Icicles on DPS and stat weights in 5.4. They're linked here so I can just post this one link from now on, and so that people can post comments on the results. If you see something that looks "off" about any of the results, please say so!
The developers have been watching various feedback threads on the new Frost Mastery, Icicles, and as you'll see, they've been paying attention. There is now a new PTR build containing changes derived from our feedback.