The class rotation is easy enough with blade dance as part of it. Now a talent I took all the time is something I have to drop for cycle of hatred. Either revert cycle of hatred and move the eyebeam CD reduction back into demonic appetite or please baseline firstblood. The spec feels so much worse without it, and I am reasonably confident most Havoc DHs would prefer to play a demonic build also.
I can see the concern of demonic appetite being too dominant if it also has the eyebeam CD reduction and that row not feeling like a choice. But honestly, most people would rather have an obligatory talent than feel be forced to drop a talent which just improves the playstyle of the spec.