I would pay $100/year for a photo organizer SaaS, that has a read-only access on a folder in my Dropbox, and let me organize my photos by time, by people on the photo, by places, or by events that I would have created. It would let me make some requests like "Show me all photos with John on it, taken on Europe, between 2008 and 2012".

Google Photos is shitty and Google already got too much information about me.