Ok, I’ve taken some time to get into what has happend in regards to UI changes.
There’s especially this thread on Github being very interesting:
It dates from 2015 and concerns were made from the very beginning! Putting the action bar on top was one of the critiques back then already. It even was mentioned that users will get an update some time and see their tool being ruined.
Only shortly after the issue on GH got locked by cketti and the user ocdtrekkie got banned by cketti for being skeptical as posted on the mailing list: https://groups.google.com/g/k-9-dev/c/NwBf_iRg3p4/m/WwGo60ncXrwJ
There even were concerns mentioned on the mailing list but no one replied: https://groups.google.com/g/k-9-mail/c/ptkurOpdyi4/m/sUiEoMIBE10J
I’ve searched the ML but wasn’t able to find anything discussing UI changes thoroughly. cketti stated from the beginning that he wants K-9 to become like Gmail.
In this thread
it was even suggested to go and ask the user base, what they love K-9 for, but that idea was completely bombed away! ;(
I recommend everyone to go and read on your own.
I even do hope that this thread/post won’t get deleted! Thx