One of the people who reported your post had this to say:
If you think unholy presence is better, prove it. Saying "it seemed better but I don't know why" is completely unhelpful.
Also, always capitalize the first person pronoun "I," no matter where in a sentence you use it.
Chimareon is not a good HC dummy, the miss debuff make it even more random for us.
Maybe its not the place for this kind of advice - so, pardon me - but yesterday i have similar difficulties, so i tried aweird thing: to DPS in UH aura as DW (at first it was an accident) - it seems to be a DPS gain (somehow - and i dont really get it why.
Anomaly? The big random? (most likely, may i add)
Anyhow, as per the last attempts, positioning seems to be an issue - the boss parried (and blocked, of course) after tank swap, so, i have to find a better place for myself next time.
Next thing is the miss debuff - during the debuff, i should wait it out autoattacking only (and in the feud phase too).
So, alltogether, i think its mostly a miss-parry-block issue, wich you can only avoid by positioning and delaying the use of your skills.