You do not want to go pure crit. If you run a sim, versatility and haste will have better scaling until you increase them; mostly versatility anyway, haste is not that important. Additionally, having pure crit is causing is suboptimal for AoE were versatility is better and significantly better in your case.
Crit > Ver > Haste >>>>> Mastery
Constantly run sims for AoE and single target with Fel Barrage and Chaos Blade and find the proper balance for your gear. Check
here for a trinket list; Darkmoon Trinket is very, very good.