I believe this is a very good analysis what s really happening in demo tree. Thank you. I hope they see it, and change some things, at least give back Decimating Bolt. Especially in PVP the lack of this ability hurts a lot.
But i doubt they do anything. All that (so unprofessional choice of) scattering the relevant talents all over the tree, the Guillotine poor design with aoe damage and no control (at least it could root the target) and many others you mentioned demonstrates their intention to keep demo spec aside. Pvp wise we are now obliged to pick only Tyrant and its subsequent talents, while he unfortunately hits very lightly. With 21 stacks his damage is about 4-5 k per hit. This is not exactly burst.
Anyway , they manage to gut half of my desire to play DF.