I’m thinking they possibly don’t test on Android (or are limited in their ability to do so)?
Otherwise what Snooj said about just going ahead anyway since it’s happened before and they haven’t gotten around to fixing it or figuring out how to, yet. Probably this one, actually, thinking about it.
I think when the reels line up and you get mostly Legendaries, the high multiplier/chest is definitely nice, but the range is also pretty wide, so not sure how it would fare on average.
Here’s Timeknight’s faction calculator, but the file seems to be no longer available:
I believe he took an average of the multipliers and expected chest upgrades from all available rooms from the optimal path(s).
Tinker Town was his most recent posting of calculated ratings, I think:
In terms of the missing map background, it’s obviously thematic though, right? 
The hero (/the dev team) keeps forgetting what the layout looks like because of darn Indrajit. Feature, not a bug.