While some people might have other reasons (still very flawed reasons for me) for believing in Sabo taking Akainu out in the place of Luffy, I think that a few simply want this to be case hoping that if this is the case, Akainu won't turn out to be that strong.
Post timeskip Sakazuki is an EoS enemy and is PK tier
Post timeskip Sakazuki is an EoS enemy and is PK tier