The Star Trek fantasy is great, but engineering and manning shields is deathly, deathly dull. How could you possibly expand those mechanics into satisfying gameplay within the Elite framework? It works in stuff like Artemis but in Elite they'd get, what - a few minutes of things to do an evening? How many people would want to do that and would all the effort be justified with a to-do list longer than many very long things stapled together?
Naval careers and wing/crew missions would be great additions, but I just can't see the fun or value in separate shield/engineer roles when the existing mechanisms are designed to be executed by one pilot.
There are many ways in which this can be done interestingly, and not coming up with ideas shows a lack of creativity (which is not to say you are not creative!). It strikes me as a lack of creativity on FD part that this role was cut off. Just to give some quick ideas;
(1) If I remember correctly, the X-Wing series had a shield system that was divided in quadrants. That means that while your rear shields were full, your front shields could be critical. In Elite this could be done in some way that the shield operator could control where to move the power distribution of the shields in real time, to protect the most right on where the ship is being stricken by enemy fire. And like that you have a skill based system to defend the shields. This might be hard to implement, but the system could be simplified as a simple panel as in the case of the X-wing series.
(2) The shield operator could also have control of the defensive systems, chaffs, point defense, and so on. And this way you have the operator controlling more than one function simultaneously during a combat situation. So, in addition to the skill based mechanic, you put some stress on the operator to keep her focused on more than one thing at the time.
(3) On top of that, you can let the shield operator control the power management of the ship to keeps things cool and operative, with some added bonus, so ships such as the Vulture, could equip more utilities than it normally can (so you can equip the defensive utilities from point 2 that make the role interesting, and to make the power management for the operator something that can be managed with a purpose.
(4) To let the operator repair broken modules while in combat, through some kind of minigame that would put some stress on the operator. Think about doing this while the ship is being shot at, and while the shields and defensive controls are being unattended in order to fix said modules, just to put some more stress on the role to make it interesting.
(5) To let the operator put some duck tape on compromised canopies.
Put all this together, and the role is more than enough. The hardest idea to implement is the first one, but I don't see it that hard anyway, and it can be simplified as it was in X-wing. Nothing suggested here requires big changes to how combat works nor to the ships. I find it hard to believe that nothing of the sort was actually done.
Are there people here who want to spend their entire sunday (...) as everybody else does the fun stuff?
The depth of the scanning/comms/engineering/shields doesn't support specialized roles in the least.
Since you expanded your post, I expand mine in response! This is why I am stressing the point of not confusing the quality of an idea with the execution of such idea. Multicrew is an excellent idea, but right now is a poorly executed one, and as of now, is not something to stick for hours per session. Let me explain what I mean; have you ever played team games such a Battlefield? I remember, back in the day of BF1942, we had players for each role in our clan. Medics, engineers, snipers, etc, and even a guy on a ship, the most boring role in BF1942. When we played matches, some roles were quite passive or slow, but it was fundamental for the team. That doesn't mean the role was boring, as the pressure was enormous when competing, and we really wanted to perform well for the team. Of course, ED is not as tense as BF, and this could make passive roles too boring, but on the other hand, ED seems to be a rather relaxing game instead. But the point is that keeping a crucial role in a team is a big motivator, and it might give you access to experiences that you might no be able to access if you play alone in your ship. It all comes down to make the roles crucial to the outcome of a situation, to force coordination between the roles, and to give enough depth and coordination within a single role.
MC might not be a central feature of Elite right now, and with its current state it will never be. But if done right, it might make Elite one of the most interesting cooperative games out there, and don't forget that there is an emerging niche for bridge command games (such as Artemis, and another one of which I don't remember the game). Just imagine the PvP between crews and the possible events that could be hosted.