I don't have any specific evidence for this, just some past experiences hosting a game a few weeks ago and not actually getting all the details from other players. I'd actually planned to host more games, but FTL (i played during beta, everybody else got a hold of it), Dishonored (boughty), XCOM (one mission a day), Borderlands 2 (unbought), and the common cold (been dragging me down for four-six days now, though its mostly over), and Torchlight 2 (unbought), housing issues (AI War friend).
So not really enough to mantis, just something to possibly check out:
If Hosting Player A has all the expansions and has selected simple/microcosm clusters, and all the other players have all the expansions, it is fine.
If Hosting Player A, B, and C have all the expansions, but player D is lacking Ancient Shadows (hypothetical: what if they're missing all the expansions?), then I obviously turn off the Ancient Shadows expansion from the game lobby. Problem is, Clusters is still selected - AND Player D can't see the same map. If Player D selects a planet, its a bit strange from the viewpoint of players A-C.
I honestly don't know if this is still a problem. I'm too fatigued to think up a witty experiment, my usual gaming group is mostly not around for a variety of reasons. Point is, if there are non-AS players, should the host be able to select certain map types? If they should, is there a possible display issue?
Edit: VV I might take you up on that. Will you be online in around 8 hours or so? If not, perhaps the weekend? Double-edit: PM sent, rather than hold a conversation entirely in edits.