I agree with you that a B/B Val'kyr will haunt first before an H/H Val'kyr and probably gain an advantage. However, for the most part I plan to use my Val'kyr in PvE such as the Celestial Tournament where I most likely will need to drag out the battles, or where I will probably need some of my pets to have higher health to last longer. Also, as a slow undead pet I do not believe that the speed will benefit it too much as it will still overall be slow (with the exception of the B/B vs. H/H scenario). The problem I'm currently have with the Val'kyr is hunting for one on a highly populated cross-realm zone. I've dont this a few times but all I ever find are B/B.