Everything I use outside of gnome puts the back button in a common spot in the top-left corner of the given window. Why fix what isn't broken? That's gonna drive me nuts.
It can't jump to a file or folder by typing, it immediately goes to search, which 80% of the time crashes the entire thing, and it lacks a ton of other very basic features where I'm questioning if people who use it even do anything more than browsing the web with their system.
KDE's Dolphin I use most. I haven't used a lot of others recently to really claim it to be my favorite though and I don't want to form an opinion on any that I used just for a short moment many years ago.
Would be nice to have a tasks queue for copy actions and the like, i.e. prevent multiple IO tasks to/from the same drive and instead do them one by one.