I am going to run a game of Trollbabe in the near future, with some aesthetic tweaks but overall the same basic thing (a bit more Claymore, or maaaybe The Witcher, than whatever it is that Trollbabe is inspired by - but I think the general dynamics will still be intact). I've run a few oneshots before though, and the multiple simultaneous adventures thing bothers me. I did not get the impression that having players waiting while scenes play out elsewhere is all that interesting for them. In many other games it's fine because everyone's split up for now, but all those separate storylines are going to directly weave into each other in the near future - that's not the case here. Also, there's direct advice in the book to not do quick back-and-forth cuts between scenes, so if a scene goes on for a while it can be a reasonable amount of downtime. If there are three players on three different adventures, that's a lot of downtime.
It also seems like there's a perfectly good solution: Farming out relationships. Friendly relationships don't have much agency but still need depicting - the GM is already hand-full dealing with the specifics of the adventure and the antagonists. It also seems like the sort of story where temporary companions to the protagonists who are not themselves trollbabes would be common and serve as an important foil to them (like Raki in Claymore, or that bard guy in The Witcher). I suspect if the GM is running these characters themselves, they'll mostly get ignored (or worse - be unable to interact with other characters without creating a weird sockpuppet bit where I talk to myself). But there's these other players sitting around with nothing to do - why not give them control over these characters?
I do get the distinct impression that this is not really the Right Idea, reading the rules - and that the separate adventures with other players staying in audience mode while someone else is having their scene is seen as a very good thing. I don't really get it though - am I missing something?