Well, I think people going for persistant big multiplayers worlds are going to be really dissapointed.
Aside from that I do share a lot of the sceptisism towards GM-mode. Considering the difficulty and time-consuming effort of level-creation I seriously doubt that any level editing on the fly will also be part of the package.
Some things I would image: * Hiding player stats from the GM, so they cannot with 100% guarantee know what skills the crew they GM have and can put up on traps and riddles (as also in above post) on the fly with the need to react if they can or cannot resolve it, adding more reactivity to both sides. * A dialogue tool for GM mode that isn't a preset-dialogue file like used in the game. It'll allow the GM to type in real time and the 'pets' to reply in real time. The players then amongst themselves pick which of the responses they gave to rely to the GM to continue. This way the GM doesn't need to pre-dialogue edit files with a lot of potential branches that'll never be met (that's for mods) but can keep things active on the fly. The created dialog however can still be saved (along with all proposed player lines, not just the picked) for actual use in modding later, in order to create more 'organic' dialogue options with players for example. This should also allow the GM if desired to make their event more easily into a mod if it proved to be a lot of fun.
But seriously, Larian should look at their ideas and think if allowing good modding and custom maps and quests is not enough, since those are required for GM, and cannot be done 'on the fly' at all. And if a custom campaign is created, what actual worth it is to make someone master it rather than people run through it as they do the campaign the game ships with. If there's no added worth, it should really just be dropped. Then again, with the schedules idea in mind, I do expect you guys to make the right decision even with it being a pledge goal that's reached...