-few cli linux tools Um. There's a lot available - even in the official repos - that doesn't show up in jolla store. And more in Openrepos. Ever tried some 'pkcon' commands in the terminal / via ssh?
-more closed than N900 = harder to fiddle/hack/program Unless you have specific examples, this is either highly subjective or simply not true.
-no raw pictures Maybe Advanced Camera can? I'm not sure. Maybe not.
-no arrows/ctrl keys to select/move into text Well, it doesn't have a physical keyboard obviously but virtual keyboard extensions for that exist, I'm using this. Text selection is tricky though, no argument from me.
-some closed parts, no guarantee I am not spied Isn't N900 partly closed too, if that's what you're comparing to? Also, did you ever read the license, TOS & privacy policy for SFOS? You might want to check out the SFOS articles in my signature.