So, rather than 16/18/20 gates, there's now only 12/15/18. That suddenly makes Tsathoggua a lot nastier if neither board expansion is in play - unless you can find another way to get rid of those gate trophies, their doom track is down to 12 at best. (Good, I think, since their 13 track makes them a little easy)
Another way that gates can move onto sealed locations - that BGotW environment that drags monsters towards the Woods.
Amanda's personal story fails if both R'yleh gates are open at once. Presumably the split gate counts for this purpose. (Conversely, assuming Silas picks the right other world, it makes failing his PS even less likely)

