The word around the street this year in Newcastle was that Mullen's form took a real dive after moving in with Willie, make of that what you will. Allegedly a bit of a party house... many complaints from neighbors. As much as he was a crowd favourite in Newcastle, most prudent punters are happy to see the back of him. As popeye said above, his mouth is much bigger than his ability.
Having said that, it's a valid point that he's probably no worse than King. Willie certainly isn't getting any better though, the difference between last year and this year was notable. These old boys tend to slow up pretty quick once the process is underway. We'll see how he goes, a good team like Manly should be able to find a job for him... but as I said, I'm glad he's not around the Knights anymore. He hasn't changed much and still isn't the greatest influence on younger guys (or any guys, for that matter).
I know you Manly blokes will put the positive spin on it and see it as a good signing, I would too if the role was reversed... but proceed with caution.
To give you an idea of how much Stone wanted rid of Mason - the Knights only have 2 established first grade capable props on the books for next year thus far - one who is still learning his craft in Korbin Sims, 3 if you count Mataora I suppose. We are super desperate for props, yet Willie was the first bloke out the door once Stone was in charge. We wouldn't be throwing away a viable, crowd-pleasing prop for no reason.