1- I would say that Ditto is in the right direction, you translated the app and it's fast. I really think that the onboard is very important and I think it should give the users to create account using email/password too. 
Two kind of accounts: Standard and Sovereign. So users could choose to create standard account and an option to be sovereign with nsec.

2- Other thing very important is have custom feeds created automatically, users could choose the topics, language that they are interested and not interested, so Ditto create the custom feeds based on these topics. Needs to be very easy to switch between the feeds or delete and add new ones.
When we onboard users, we really need to show some feed with the language the user understand.

3- Ditto needs to fix basic bugs.

4- A real PWA app is important. They way works now on mobile I don't think is as good as a PWA.