I feel it really depends on the size of the realm as to the importance between a marshal and the general. In smaller realms there is no real point to appoint two different people to the roles as the general might as well take full command anyway, and most often ends up with the marshal/vice-marshal position. Though of course this is only my view on the matter, as most of the realms I have ever joined are either small, or became very small due to certain events.
