You're giving up 1170 armor. In ICC you're going to get hit more often, which is why armor is more valued than avoidance. That extra 1.5% dodge means you'll avoide 1.5 out of every 100 swings on average, but due to RNG you never know when that will be. 1170 armor is almost always useful (sans magic damage).
You're not Exp capped but you're way over hit-capped. So losing the Exp for hit is a threat loss. THough you're glyphed for threat so it's more a personal choice.
Regarding gemming. If the socket bonus isn't at least +9 per hybrid gem, it's not likely to be a surviability increase to hit the socket bonus. Typically this means you only go with something other than +30 sta for head and waist. Usually. It depends on the sockets.
The cookie cutter suggestion is to stay with Cataclysmic, swap most of your hybrid gems for +30 sta (keeping the head and waist to hit the +9 socket bonuses and activate the meta - I wouldn't worry about hitting the leg's +12 because it requires 2 hybrids or only +6 per hybrid). If your threat is okay you might want to think about swapping some of your threat glyphs for surviability glyphs (Last Stand, Shield Wall, Blocking, and/or Taunt though that's not a survability glyph).