I might have misunderstood something,, but to my eyes feint was always a bit off. attacking wits, made it very hard to use against exactly those types it was needed against. this might make sense, it shouldn't be easy to negate another char's advantage that they had paid well for, but then Beat is a far better knack to use against high wits / panache chars that parry a lot, the characters that you might want to use Feint on are also quite hard to feint against.
So my suggestion for feint:
Feint (Swordsman knack)
by spending one RP on an attack roll, the attacker can reduce the TN to be hit of the opponent by 3*his rank in the Feint knack against that attack only.
I was considering only a factor of 2, but spending a Ressource should give some Ooomph to the action.