IMHO
1.- Pros: In any multiplayer game you can add a lot of appeal to those players who would like to start multiplaying but lack the skills to do more complicated roles (Torpedo shooting, manouvering) if you give them roles with little or no effort to be done well. This feature would no doubt attract to multiuplayer many guys who would otherwise not have interest in the game, or at least to play the game in multi. You know, it's like the guy who plays the small silver triangle in an orchestra....he would not participate if there was not such a simple instrument to play.
2.- Cons: Is it really worth to complicate the project to include this extra role? Are you aiming at a large scale, wide public sim? If you are looking for a niche in the market occupied with serious gamers who want realism, I think many will pass on that feature, while casual players will probably not buy a sim with such a steep learning curve just to play as engineer.
My 2 cents
