David Price KO'd Joshua in sparring. this is a 100% confirmed fact. Why couldn't he do it in front of 90,000 at Wembley? HE COULD!!!
Briggs would be a nightmare opponent for Joshua, a guy that isn't at a size disadvantage, who's quick handed with lightning in his fists. At least for the first 5 rounds. Personally, I don't think Joshua survives the rough early spots to take him late (his stamina isn't great either). No way Joshua wins a shoot out vs. Briggs.
Briggs would make Joshua look like Ali. There's a slight Joshua could implode but he beats any version of Briggs 9/10.
I'd take Joshua over 1997 Briggs, you know the one that lost to old, slow George Foreman. Today, AJ KO1 over Briggs.