Updating is a hassle

I don’t know who exactly is at fault here, but this is such a bad experience.

I had OpenElec 6 (kodi 15) on my Pi3 and tried to update it to the current version 8 (17).

1) movie db is empty after update. why? (could restore it by renaming the last backup)
2) using the backup worked except for the posters and fanarts, most of them are downloaded again and are now different. why? old thumbnails are still there
3) new skin, looks good at first, but I can’t see fanarts anymore, movie text is useless, need more clicks to watch a movie
4) confluence skin is now missing features like the list of movies I started
[5) I learned here I can modify skins, but openelec is a read only fs]