Reading into the Puppy Propaganda are we? ;)
"A Thousand Sons" makes it abundantly clear the Wolf Priests get their powers from the same place everyone else does, they just choose to ignore (perhaps willfully) that their psychic powers come from the Warp, just like everyone else's.
I don't think Ahriman is exactly an unbiased source. Not withstanding, in terms of why wolves? The Custodes are busy, and the Wolves have proven themselves that perfect combination of both willing and capable to do whatever it takes in the name of the Emperor. They just seem the ideological choice, high levels of veal, high levels of dicipline. Nothing to me says Wolves more then the deciding moment in the fight between Bear and Amon. That should be all it takes to explain why packs of wolves are following the legions around.
I know it's a typo but the idea of the Wolves having more veal tickles me no end... :)
That said, given Warhammer's general tropes, could it be that the Wolve's use of the warp is substantially different? I'm thinking along the lines of runes/runic magic/dwarfs etc. Maybe this could account for some of the discrepency post Nikea, just a thought given the various problems, the use of the Aegis, and so on.
