A 1960 Sonny Liston or A 1974 George Foreman Personally, I'd want to see him against Liston a little bit more. Has all the makings of a classic war
Neither. More like non-jabbers or a non-mover. Bonavena or a Lyle or a Weaver type guy. Shavers would be fun and exciting & I'm not sure Mercer would be in good enough condition to absorb like Cobb or Ali did.
A Liston -mercer could be a nice battle ,neither man backing off .Mercer no doubt loses but puts up a great display. 74 Foreman ,more wild,slightly sloppy but maybe hurts mercer to the point of a stoppage.