As a DK, Stamina, Melee, Heavy armour, I am in favor of keeping it...
Why ?
Because it is the ONLY (and I really mean only) class spell we have that is better in my Heavy Armour set up than in the standard Light Armour DK set up, since with this "Flame of Oblivion" spell up (it is the only magicka spell I have on my 2Hander bar), I am still getting magicka "regen" (thanks to heavy armour "Constitution" passive).
I can even keep it up indefinitely with either 6K health (...) or using any low cost ultimate on CD (Battle Roar passive).
Any other class spell is better in another armour with magicka heavy character as all of us know. So if there is one class spell, kind of "designed for me", it is this one.
I only wish :
_ radius would go up from 5 to 6 or 7 as it was the original radius of the much more powerful and impactful "Talons".
_ scales somewhat on stamina (as we can see light armour, magicka-based DKs don't like it anyway)
_ does not fade away when I switch bar (would be consistent with other buffs like "GDB", "Spiked Armour"...)