Actually, what you’ve quoted is Brasha asking the question what ever happened to all the noise suggesting Wallis is going to re-sign with the Dogs? Implying that he might not be re-signing with them, and is talking with another party.
So if your “Brasha was right about Wallis” comment is in regards to Wallis re-signing with the Dogs based on the above comment, you are mistaken.
Which isn’t to say that he doesn’t have sources (I have no idea) and perhaps we/someone else were talking to Wallis. But unless he posted something after that he can’t be said to be right.
His 2016 was mid 20’s disposals & 1 goal a game - thats a very good return by any standard. The problem is that every season before that was well below that standard & even his 2017 was down on disposals & 40% down on goals. Add in the 2018 season of only 1 part game & you effectively have 1 excellent season, 1 very good season & the rest is only good verging of disappointing given his draft position & then salary at GWS. If he recaptured his 2016 form absolutely he would be an awesome pickup but that season was clearly the exception not the rule. Massive question marks on him & nothing that indicates to me that GWS might undervalue him (like they did with Smith).