In the older vampire counts book I have, the only 'active' ability of the Strigoi is " Summon Ghouls", which doesn't really translate into WFRP, save for the vampire being surrounded and served by ghouls.
That said, Curse of the Revenant (So strong is the desire for some to continue living that they defy death. But this has a price the eternal thirst for the blood of the living, gives the 'Regeneration' special rule in the army book) and Infinite Hatred (give re-rolls to failed to-hit rolls in the book) could be translated into actions, as well as some undead-bolstering powers in lieu of detailed necromancy spells. A Strigoi should also have all the powers of the Crypt Ghoul('No Escape, No Hope' and 'Seized with Bloodlust').
The other bloodline powers in the army book make Strigoi even more powerful physically than other vampires. And let it turn into a bat (I could've sworn that was a von-carstein power).