Text search across full message history has been part of stable production releases (on Android at least) for a decent long while, just fyi. (Desktop client has also gotten better (but is obviously far from perfect); those messages end up retrieved later on, fwiw).
Not sure if it's because I run the beta version but I have the search feature in individual conversations and use it often. There is a desktop app and I agree it's not the best. The desktop app is the only place I've had the retrieving messages issue. So really the only gripe I see you having is no decent non-phone client. For me that's not a show stopper at this point in exchange for a secure, easy to use application.
* no search (big one for me)
* no web client ( another big one)
* app gets stuck in "retrieving message..." if there is a poor signal like travelling under a tunnel
and there are many cosmetic ones like the ones you pointed out.