Really, the easiest feasible way I can think of only lies within the BBR and a debate/vote when conditions that people want a temp ban are met.
Right now, most of us have some kind of thing we're looking for in regards to metaknight's superiority in brawl and a set of criteria that must be met before enough is enough; however, as explained by Adumb and others before, this criteria has already been tainted because our preferences may have shifted towards leniency and/or strictness in criteria after the problem already arose, and thus we cannot agree upon one or a few people's suggested criteria, even if they seem logically sound and reasonable.
That's why pro-ban fights an uphill battle that is, at the moment, slowing to a crawl, even if more evidence supports pro-ban's claims. Pro-ban has all of this evidence and proofs, figures and graphs, but how can one create unbiased criteria utilizing these sets of data if stances pertaining to the MK ban have already been made? Furthermore, how can one turn this from a pretty convincing argument to a critical and conclusive evidence? Pro-ban has been very close to this, but it really did not affect much in the long run as the discussion progressively deteriorated.