I dont understand why OP readers dont think there is a power limit cap.
Akainu is probably only slightly weaker than a prime WB. Yes he took a few punches from WB but he was far from finished. I doubt akainu cannot hang with the yonko. There is a limit to growth though, legends are legends for a reason, beacause they get hyped over time. Only thing we have from WB and garp from back in their hay day is that they were able to keep up with rodger, and none of his feats are thoroughly explained. With the recent statement from Kaido we can assume that WB was as strong as kaido or a little stronger but not to the point where even in his prime he would be able to roflcrogstomp him. I feel that in a 1v1 fight that Akainu would beat WB, with no distractions or other potential threats, and the same can probs be said for all the other admirals too.
Anyway. It depends on the representation of the EOS Villian. Akainu would be the representaion of the Marines, or WG. BB would be a representation of luffys stuggle to be PK. Chances are that luffy will vs. the WG before BB...