Over the past couple of weeks, Blizzard added a few interesting new items to the patch 5.4 PTR in the forms of new glyphs and possible trinket drops for the Seige of Orgrimmar raid. Now, in both cases, these are pretty tentative. The trinkets don't have proper names yet, and the glyphs are all marked as NYI (Which stands for not yet implemented). This means they may not make it to live servers, or may not make it in the same form. Still, the information's intriguing enough that it's worth taking a look at it.
Glyph of Regenerative Magic is looking like a very strong choice that may make it into a lot of glyph slots. If you misfire your Anti-Magic Shell and it doesn't completely absorb all possible damage, this glyph gives you a second chance by reducing the cool down. I can see this being useful on magic-damage-heavy boss fights and PvP for sure.