The Teentch power is massive. I play against a chaos player who have excelled using it, often with a heavy stubber pinned in cover, using it to blindfire against enemies in heavy cover!
I was reading the new PDF and was wondering about this, the wording from the PDF is;
"Tzeentch: Once per round, a single fighter may ignore all negative modifiers when making a Shoot (Basic) or Shoot (Double) action."
To me this seems to mean that the Tzeentch power couldn't be used with Blindfire (Double) as Blindfire is it's own action seperate to Shoot (Basic) or Shoot (Double). Not sure if i'm reading this right or wrongly. Food for thought =)
In general I like the tweaking made in the PDF, though a few too many similarities to Cawdor but with a better skill selection (ie access to Ferocity). The psyker powers/witch are still a little disappointing (imo) though are handy in the original gang war style campaign (as money makers).