I prefer the other solution to pilot XP suggested, but this seems like it could work really well.
...The ability to drop with injured pilots from the No Time to Bleed mod. Might want to consider something similar!
FreiBiers option is good as well.
The option I went with probably, maybe, forces you to simply choose. You take a bit of all skills and later harder to specialize in anything. You specialize in something and later will be harder to take from other skills.
No Time To Bleed: One idea was that people would use more pilots as well, not sure how well it would work with that.