Holy jesus fuck daemons of khorne can take the axe of blind fury now.
My life is complete.
Um, that's been in the CSM FAQ for about a year now. And Daemons of Tzeentch still can't take the Scrolls of Magnus, though they're a similar object to the Axe in how they're written (just for MoT instead of MoK).
Still, I really think the Black Mace is an incredibly better option than the Axe on a DP. A lot of what you're paying for with the axe is the AP2 at initiative value--something the DP already has. Yeah, the S and attacks are stil worth it--but wouldn't you rather have Fleshbane, the chance of IDing enemies with every wound you inflict on them, and a 3" DOOM aura for a mere 10 points more, plus the same bonus to attack #?