I'm a big rock'n'stoner (700 hours) but I think you're stretching it a bit.
Of course there's knowledge and experience to acquire, but it's not the main progression system. They are needed to beat harder missions, but the same could be said about 90% of the games out there.
On the other hand, I will agree that DRG does allow the player to express them more than your average RPG, because upgrades won't beat haz 5 on their own. You still need to know how to play the game, and that is made of little know-hows and techniques like the ones you listed.