No way anyone with any real eye for fighting would dismiss J Walker for his loss to C Anderson. Now if Walker comes out and continues to do the same antics before actually engaging with the opponent, then yeah we can start to discredit him. But again anyone with an eye for the sport can tell that Walker was going methhead on the feints and Anderson caught him with massive punch that really rocked Walker and it was all over from there. And even still Anderson couldn't even drop him so it shows that his chin has some resiliency to it.
Plus fighting against Jon, Walker wouldn't have to worry about any power punching strike. A kick to the noggin would be the thing to worry about but can Jon even lift his leg up high enough to reach Walker's noodle? However I think a fight with Jan would not be a good matchup for Walker just because of Jan's power. Either way, I think Walker is legit but needs to cut out his bullshit feint spamming to start the fight.