Is ratings enabled? The block by design uses most recent instead of top 10 when ratings are disabled because without ratings there is no metric for determining "top" galleries.
Reviews were enabled, which include ratings (might not be the same, kinda weird having 2 different methods of rating potentially available). I recall that regardless of the ratings being enabled or not that all blocks show up on root but the Top 10 code was ordering by latest (which as you've explained is likely intentional). You can leave this one be as I've since deleted the install and can't refer to it.
GALLERY_POPULAR is using the wrong parameter: "mode" when it should be using "sort". However, beyond that, it's still not ordering by rating, and I have no idea why. SQL looks fine to me.
(also "top" is not a valid sorting mechanism... it should be "average_rating")
(also "top" is not a valid sorting mechanism... it should be "average_rating")