Passive skilling should definitely be the "main" method of upgrading skills, it hinders the ability to grind your way to victory. Doing well in a match should give you a nice boost to your skill progression, but I don't think that should be the primary way to get SP, that makes that guy with the 5-10 KDR - the one that screws you over to save himself, or pick up a kill while you get nuked at the objective - progress through the skills much faster than you, even if you're trying to be a team player and what-not.

One of my favorite things about the time I spent in EVE, was that if I knew that I wouldn't be able to play for a few days, I could set up a training queue, with a bunch of smaller skills, until I had it filled up to 23 hours or so, and I could just dump a level 5 in there that would take up the next 3 or 4 days to train. Then when I would finally be able to log on, -Ta Da- I would have a shiny new level 5 skill to play with.

That type of skilling makes being a newb so much easier, especially if you are starting with friends. If you are gonna be gone for 3 or 4 days, you can just put a few skills on to train, and while all of your friends will get a bit ahead of you with SP gain from matches, you wont be out of their league.

I personally would love to see the skill training system in Dust, look more synonymous to the skill training system in EVE.