I feel like having a glyph that generates shadowfury in meta form was amazing but the way things are looking now it seems like demo locks still have to hard cast since that glyph was removed and will be sub par especially without pocket heals and long casts times without going into demo form which will quickly fade once all shadowfury is consumed. Also, the time it takes to build up will be gruesome for the demo lock in pvp... I may be completely wrong but please enlighten me.
I do not have a Beta account so my knowledge is strictly off youtube and forums. I love having high defenses in PvP and living longer than just being the power house, and I just wish blizz would make demo as efficient as the other specs.