I agree. Being the right type of person for the job is the most important. Degrees won't get you the job, nor will memorizing every unit/weapon in the CF or your year in Krakow learning Polish. What these seemingly irrelevant things will help with though is separating you from the all the other right people. Your pursuit of education can show a lot about who you are, even if you never speak a word of that Polish in your entire CF career. Now I'm not a recruiter, but I'd venture a guess that between two applicants with all other things being equal, they'll take the one with a better academic history. The bottom line is that improving your credentials DOES make you a more attractive candidate than someone who's been flipping burgers for 3 years instead. I don't mean to sound elitist, but that's life.
I would also echo the others and say to study something that you're interested in outside of a military context. Maybe that is military history. Or maybe it's German, or chemistry, or tool making. It will give you something to fall back on if for any reason you find yourself out of the forces. Studying something you're genuinely interested in will also help you do well- improving your chances of getting in. Generally speaking, anything the CF will NEED you to know, the CF will teach you. I wouldn't be worried about taking things like Leadership courses in college. In terms of an application, I'd imagine volunteer experience that demonstrates leadership would probably be even more desirable.