Between the two I choose skill. But skill and athleticism don't make up 100% of boxing, because there's also heart and ring IQ.
Skill all the time. Zab Judah was more athletic than Floyd - better speed and way more power, but look at their careers
Exactly! That’s why NBA, NFL, and Soccer players don’t necessarily make good fighters. Basketball, Football, and Soccer use 1 ball to play. Boxing takes 2 balls.
The answer must be to favour athleticism. It doesn't matter how skilled a 3ft tall 70lb boxer is he cannot beat a 7ft 300lb behemoth with little/no skill. Alternatively, a marathon runner who's never laced up a pair of gloves, would have to be favoured against a very skilled fighter with only 10 seconds of gas in the tank before he's on his arse. Therefore, athleticism must be the more important attribute. As for an ideal ratio, it's difficult to say because you aren't comparing like with like and there's no logical tradeoff between skill and size. If you asked me to stop being boring and just give an answer to a dumb hypothetical I'd say I favour athleticism 60/40.
I do not think there is an ideal 'ratio' since the more the better of both attributes . Of course athletism is the most fundamental attribute where boxing skills are built on . If this would not be the case boxing would not need weight classes at all and a very skilled featherweight would fight and beat a heavyweight.