IMO, Charred Remains was horrible, and almost impossible to tune properly without screwing up the alternative builds. If they had only removed CR and buffed RoF to enable FnB AoE against medium-sized packs, and added the Artifact on top of that, we'd have a much better spec than what we have now.
It feels like Blizzard thought that "not much change needed, except for some polish" meant the same as "lets make some random changes without really putting any thought or effort into it". Rarely have I seen such a poor and lazy design as in Legion destro. We just got several baseline abilities turned into talents, supplemented by a couple of very lazy, unconnected, stand-alone new nuke designs: Channel Demonfire and Dimensional Rift. Oh look, a nuke with cooldown, without any interaction with the rest of the rotation. How inspired. Player feedback managed to improve the initial mess a bit; such as giving Incinerate at least *some* interaction with something (the Rifts) instead of being a completely bland filler, making the Rifts instant, and allowing RoFs to stack. The "spec" they tried to initially force upon us really underlines the fact that no effort whatsoever was given to destro. And even worse, since it was introduced so late in alpha the players didn't really have enough time to fix it. The designer thought process probably went something like "Hey, destro has a spell called chaos bolt. Chaos. Random. Lets make destro playstyle really RNG oriented. Phew, now that that's done, lets get back to designing the other more important classes."
Fire mage, for example, is like from a different planet in comparison.