Many games have some sort of role for the players, especially in multiplayer games. Medic, Sniper, Rifleman, AT Specialist in Battlefield, Healer, Tanks, DDs in MMOs, etc.
Now, in many games, there are incentives to specialize in a certain role, allowing access to better equipment for this role. Most of the time, you archive this equip by playing a certain amount of time, gather XP (by doing the roles job), or archive certain goals for that role (heal 1000 players, deal X amount of damage. Battlefield Bad Company 2 and Quake Wars are good examples for that.
Alternatively the player gets "better" in the role by pure stats. They get more health, they heal more etc.
In contrast to that some games have certain roles, that a player can fulfill just by picking certain equipment, that everyone is able to pick. So in theory, every player is as capable of fullfilling the same role. The difference is in the skill of the player and the depth of the role to fulfill.
The game i have in mind is a coop crew game, where you manage and controll a ship, much like Pulsar: Lost Colony, but much more complicated. Engineering would mean to flux the vents and stabalizing the emitters, which means to have complicated "mini-games" to archive a certain goal: Activating the engine and keep it running. Similiar to Space Station 13 maybe.
So, either i could go the leveling way: The engineer gets traits and stats, what make those minigames easier for him (make something move slower, get a better result). The other thing could be the learning way: you have to learn how to do things, make it more "realistic" and with different (scalar) outcome.
I tend toward learning the about the mechanics. The idea is that you might have more than one person for a certain role, like a chief engineer and many other working in engineering, teaching them the in and outs, maybe even on equal terms. It also would make the game more hectic and thus more reliant on communication. A hard level base would mean, that someone is distinctivly better, if he is a higher level. The higher levels would need to do most of the work, hence their boni are just to good to waste.
On other hand, for roles with less of a learning curve, that wouldnt make that much sense, since mastering it is a lot easier. In that case, it would make sense to have one with skills in this role. But, if you have a pilot with skills for a faster ship, it would be wasted on a slower, but less manouverable ship, where a pilot with talents for better mobility would be far better. For a premade group of players, that would be alright, but if you got drop-in, drop-out, that would be hard to balance for.
What style of role specialisation (leveling vs learning) has what advantage and disadvantage? What would fit better to that syle of game im working on?