What argument can I formulate. I only think that Cap has enough figthing abilities, strength , speed and agility to provide a valid challenge to Slade and even defeat him. I'm not saying Slade can't beat cap. He sure can but I just cap winning more often in a figth with no prep and no battleplace conditions that would give advantages to one or the other. About Bat's and Lex, can't name the original issue. It's in Portuguese and the issues are diferent. But I think it was already a few years back. I think it was Batman and Superman Public enemies when Lex was stiil the president of the United States. I'll look for the issue and tell for sure after work.
Cap isn't beating Slade, Iron Man isn't beating Lex either. That's your opinion... not mine. I do think Cap has what it takes to beat Slade and I think Iron Man has what it takes to take down Lex (even if his armor was designed to figth superman, the truth is that Lex even with the armor wasn't a good match against superman. I mean, Batman has defeated Lex in his warsuit without prep.
Joffrey should win. I know he's actually too annoying but when someone is trained with some types of weapons it also aquires somekind of H2H experience and becomes stronger and faster. Joffrey wins. Unfortunately.