Wes Janson is a counter to PTL token stacking. Let's assume he's running VI, so he gets his choice on who to pick on. Now lets talk about opponents...
Wedge will not want to PTL F+TL to destroy a TIE, since he won't get either of those actions.
Soontir will want to make sure that he arc dodges, which is hard to do when Wes hasn't already moved... plus since he doesn't need to hit with his attack, a K turn + attack is enough to strip all of Fel's tokens.
Any 1 Agility ship would prefer to keep their Focus for offense, so B wings, Y wings, YT, and Albino Rhinos will basically all lose their action (unless it was spent on BR/Boost)
Moldy Crows won't be able to stack focuses anymore
Recon Spec will no longer be such a great thing for firespray's defense
FCS will be shut down
Ordnance will be shut down
Seems to me that Wes is NOT a one trick pony. Almost every list out there has something severely affected by his ability. And for the ones that don't, you've now paid 9 points to get 8 PS on your rookie, which isn't a horrible trade off. You might want to consider though the option of ST on him instead of VI... Though being able to strip Wedge and Fel is really cool.