The search definitely is a sticking point. Its just not there yet, thats a big one. There are weird quirks like follower counts jumping around - that one doesn't bother me but I can see people being annoyed with it.
The one thing I don't know how you solve is the key pair thing. That attracted me to Nostr because it was so familiar, but I can see it having the opposite effect on people. My guess is some clients will obscure that piece while others will make it easy for users to rhn with it who want to?
In defense of the clients though, it was so bad early on. Things crashed constantly, it didnt scroll well, it was a bad experience for people coming from something more polished like Twitter. Its come so far. I worry that people left early on because they had a bad experience and haven't given it a second try now that things are leaps and bounds better.