1) Yes, this is one of the things we have to address when we'll a real back button. The current back functionality is "hidded" and does not work on iOS (without an external keyboard), the idea is to have back button somewhere and make it also affect sidebar and note list.
2) This is a little controversial for us. I get the usefulness of this but our idea is not to make changes inside user's notes without an explicit intention and changing a note link inside notes follow in this category. Automatism like this can be super-useful but also lead to usability problems.
3) We recently have improved this behavior making the note editor not losing focus when a tag is edited/deleted but the note list still changes to "All Notes". We will eventually change as you suggested (first option) but at the moment will break an incredible amount of small functionalities.
I wanted to second suggestion #2 above as essential to expanding Bear's usability. I understand the argument to not make changes inside a user's note, but I would say that if you make this functionality clear (exposed) to the user, this would actually be the user making changes throughout many of his/her own notes. In fact, this is directly parallel to changing the name of a tag and having that tag change throughout all notes, in terms of its application and the fact that it is essential.
For example: At the moment, if I link note 1 (let's call it "Index") to note 2 (let's call it "Hello" as above), and then change note 2 to be called "Hello World," the link in note 1 ("Index") creates a new note called "Hello," rather than linking to the original note. Similarly to having a tag name change affect the tag name in notes throughout the program, the lack of this functionality in regards to linking note titles kills some of my ability to use Bear in the way that I was intending. (I am trying out Bear Pro currently.) I have a note that includes comments on my day's work and also functions as an index-level view of other notes, but with the current functioning of the program, I either have to remember which notes are linked from that note, or never be able to change note titles, even when it would make it easier for me to reference them that way.
Please consider changing the behaviour of the app to allow for this sort of dynamic linking. For me, this would be a major item that would allow me to commit to using Bear Pro!
I see that Bear have two kinds of note to note links:
The ones you make with [[My Note Title]] that uses note title as reference
Links (x-callback-url) that you get when dragging a note into another, that uses note ID as reference.
#1. get confused if title changes, if duplicates, or if a copy is in trash.
#2. Seems to be much more stable, independent of title changes, even though links still shows old title.
Maybe the [[Note Title]] links could use note ID instead? And update when target note title changes? (But without updating modified date, like when you rename tags in sidebar, non of the notes affected changes modified date:)
[[note links]] works differently back in the day: If you didn't have a note which matches the title the link was not be highlighted (not clickable). We changed this behavior and now if you click on the link and there is no match a new note with the same title is created. This because people who use this feature to build Wikis find very handy to write the link first and the note later. If we use the note ID the link will never get back in the create-new-note state, which concern me a little because of how [[ is used.
Also, I guess people who want the link updates don't want only the ID but also the title to change.