Differences between ibuffer and dired

[Deniz Dogan]

Why are there so many inconsistencies between the ibuffer and dired
keymaps? E.g. "U" in dired unmarks all marked items, but in ibuffer it
does "replace regexp". "u" on the other hand acts the same in both
modes.

In my opinion the modes are so similar in their use cases that users
should expect the keybindings to be much more similar than they are
today, at least for such basic things such as unmarking items. So why
are there so many differences between them?

-- 
Deniz Dogan