1. Your haste rating is way too high. Soft cap is 360. You are currently at an astonishing 681. You need to shed a serious amount of haste gear and replace it with crit instead.
2. You have 5 12 SP/10 spirit gems in your current gear. I suggest replacing all of these with 23 spellpower. Spirit is not a statistic focus for discipline as talented mana conservation is greater as discipline, and you gain no additional benefit from the stat (unlike holy).
3. I take it most of this is your shadow gear. Your meta is a DPS meta gem, and you have 111 or so hit rating.
Basically, you need some serious gear improvements and to switch some gems. Spec is fine, as are glyphs.