Been using Thunderbird for a few years after using mostly webmail and it has been a
mostly good experience. The UI revamps have definitely split the room somewhat, but honestly, Thunderbird's UI progression feels much better than Firefox's, and I have actually gotten used to the way Thunderbird looks and functions without too much pain. The information density is still generally alright, the tabs look like tabs, etc. The only thing that really tripped me up is the inconsistent hierarchy between the tabs and the sidebar, and I am not really that torn up about it, to be honest.
What I really think Thunderbird could use is account sync. For me on NixOS (how do you know if somebody uses NixOS? Don't worry, they'll tell you) I might just set up some secret data in SOPS and have an activation script ensure the accounts are all present, and then IMAP can take care of the rest. But for the general user, and maybe even still me, Firefox Sync support for accounts and extensions and more would be amazing.
Speaking of IMAP, JMAP support is another thing I'd love to see.
What I really think Thunderbird could use is account sync. For me on NixOS (how do you know if somebody uses NixOS? Don't worry, they'll tell you) I might just set up some secret data in SOPS and have an activation script ensure the accounts are all present, and then IMAP can take care of the rest. But for the general user, and maybe even still me, Firefox Sync support for accounts and extensions and more would be amazing.
Speaking of IMAP, JMAP support is another thing I'd love to see.