On Destro - Wouldn't mind RoF having a minor glyph to make it castable on targets or having an 8 or 10 sec duration to take some of the clunk out.
On Demo - I don't find it hard, so much as awkward to play. Entirely personal preference, but I just don't like ToC as a nuke, the HoG gaming, etc. Removing the CD from Meta would help, but the spec just 'feels' off to me. In the '6.0 wishlist' world, I'd still really love to see it become a pure melee spec with DoTs and pets (basically think Unholy DK with DF instead of Runes).