Update: It has been confirmed that the default will be changing back in a future update.
Since the gallery is now defaulted to being sorted by 'Popular Now', I noticed that the majority of recently uploaded creations are getting very, very few downloads, whereas before everything used to be downloaded at least a few times. It isn't very fair to those who don't have tons of followers but still want to share their creations with others. Yes, users can easily switch to sorting by 'Newest', however most players likely won't bother/notice. I'm sure many don't care about the gallery or how many downloads they get, but I've personally enjoyed sharing my sims and builds a lot as of late. No one seeing or downloading kind of defeats the purpose of sharing, though.