It would help Wlad's, after Wlad knocked out Briggs, gained another title and got revenge for his brother.
No briggs recieved supernatural power for this fight so it in no way affects Vitali's legacy if he loses.
I think it ruins it simply because there is already such an argument against both Klitschkos when it comes to era and competition. Wladimir has much more "legacy fights" whereas Vitali is just one bad mofo whose "2" in the L column (essentially a 0 or 1/2) is much of where his legacy lies. The only two wins of Briggs' that I was aware of are the only two worth a damn: George Foreman and Siarhei Liakhovich. Vitali would be nice to add to the resume, which is littered with relative quality losses.
If he gets KO'd by one of those bombs it would just hurt a little on his legacy. If he gets outboxed by Briggs, it would hugely affect his legacy. But that will never happen.
