Demo's niche is obviously being clunky at everything it does.
On a serious note,
didn't they state that they were moving away from static AoE 'rotations' ?
Carrion swarm was nice mass-interrupt utility too.
As for Shadowbolt, it feels slow: It was only second-half of the of the expansion that demo felt 'fluid.'
At max 2.2s cast for Shadowbolt with a proportionate damage nerf (also secretly buffs resource generation).
GCD capped Soul-fires are also wrong: they did adjust Elemental's Lava Burst for that reason.
A damage buff would be more appropriate.