Gladly. Basically, Bloodthirsty neuters the one major equalizer for BD's inferior combat stats: Flying. It's the inverse of Sike's point about defensive hindering, only worse.
Blood Demon doesn't hinder the enemy non-flying creatures, but it also isn't being attacked by them so it lives longer. Hindering your opponent's creatures or not isn't the difference between "bricking" in that matchup or not. Especially when YOU have the choice of damaging every creature your opponent has or just the mage.
On the other side of the coin, if your opponent's creatures are nonliving or living but
undamaged your Blood Demon will be able to quickly make it's way to the enemy mage. Dark Pact Slaying on the other hand cannot do the same.
Against resilient non-living, yes. Against iron golem? And since this is about Reapered BD vs. DPS, the latter is strictly better offensively. Also, DPS is better against IG than FH.
...who the **** bothers to try to take out Iron Golems???
Which you can put on DPS who can inflict more damage on the mage. Or alternatively can be dispelled/wanded out by control builds. I can also put vampirism on him if I wanted. And on... and on....
You're only going to be able to put a
limited number of enchantments on your Blood Reaper. If you use the Dark Pact Slayer you're going to need more
defensive enchantments like Eagle Wings or Vampirism or Rhino Hide or Regrowth to keep it alive. Blood Demon doesn't need those, meaning you can
put Bear Strength and Mongoose Agility on it right away. There is an opportunity cost to things, you know? And especially with the Harshforge coming soon you won't be able to just put as many enchantments on things as you want to anymore.
What's the point of not attacking when BR is an offensive ability? And you're gonna give your opponent more opportunities to nuke BD at lower heath and armor?
I know this may be hard for you to grasp, but occasionally
not attacking is better than attacking. It depends entirely on the situation.
Where Blood Demon could excel is in potentially aggressive Pentagram strategies where he and Scourger have natural protections against spawn camping.
Um, ok? I have doubts that a Warlock could sustain summoning multiple level 3 demons out of the Pentagram with the low channeling, but whatever.
I disagree that he's the default BR most Lock players, because DPS is just more versatile and has fewer match-ups where his traits brick.
Dark Pact Slayer is better at attacking things you don't want to attack with your Reaper anyway, and the only major "downside" you mentioned is that the Demon and your opponent's creatures likely won't hinder each other.
Except that is exactly what you want in most cases anyway, so...