As a raiding demonology warlock, I find that Ghostcrawler's design intentions really make me pleased. Right now, if you want to do good DPS as a demo 'lock, you're going to be in the melee group as much as possible to get the most benefits from Metamorphosis and Immolation Aura, while at the same time staying stationary to turret out your DPS. In Ghostcrawler's plan for Mists, the necessity of melee-range spells is going to be situational. No longer am I going to be pestering my raid leader to put me in the melee group for Zon'ozz, and I should be able to stay at range and enjoy such benefits there as much as I can (which, at least in my perfect world, would include less movement).
It'll be interesting to see how this kit plays out in the end. It always seems to be one of those specs that gets changed around a fair amount in one way or another, and Ghostcrawler does say that Blizzard is looking to make a home for demonology.
So have faith, fellow 'locks! Things are looking evil.
Ghostcrawler's full statements, after the break.