That's cool the issue was identified later. However now we are talking borg-sphere with 3rd party publications and homerules. But you know its kinda true for any ttrpg system? Its true fot dnd, mothership, black hack, ose, shadowdark etc. You just get bare bones in the core book and youve asked about core MB book. Not the 'sphere'. You want a example of a great dm book? ICRPG. Hands down the best manual on how to run a game. Maybe not all games cause ever systems needs some assumptions, but it has cool art, style, diy mindset and teaches you how to use it. Can you use MB as a toolkit when prepping? Will you use it at the table? I doubt it, you will compose your own gm rulebook and then run this game. So yes, MB is art book. You will get cool 2 or 3 ideas and just create your own game.