Lasers said:
"You know, psykers keep coming up as the be all end all, but there are a few things that really just cut them down to size, one is the Culexus assassin, homebrew some stats and give him a nasty little effect against psykers that does damage based on psy rating(Make him a vindicare with a pumped up package from the radicals handbook)."
Culexus Assassins are actually quite easy for a Psyker to deal with: Telekinesis + heavy object(s) = win.
Is there any reason to believe that a Culexus Assassin is any less capable of Dodging such objects than a Vindicare Assassin? If not, then 'win' is not the outcome the Psyker should expect.