This is what makes Emacs more flexible than Vim to the point where there's a very faithful reimplementation of Vim for Emacs. Couldn't do the opposite, even if you wanted to.
Emacs out of the box comes with a menu system. This is very good and useful for newcomers because it not only gives a familiar feel, it also helps discovering functionality. However, it is no coincidence that a lot of power-users turn off menu and toolbar, as evidenced e.g. by Steve Yegge's "effective emacs" tips (https://sites.google.com/site/steveyegge2/effective-emacs#it...). Now, not every user is a power-user, there is of course a spectrum, but to me it is fairly clear that the way Emacs is designed, mouse-based usage would be a limiting factor.
Those that take interactive strings, maybe - but for those that take buffer positions or regions, which seems to me like a plurality if not majority, I would love to be able to invoke a command and then click+drag somewhere I want to apply, rather than having to set the point there and pop it back when done.
Or the other way around, select a region, right-click to get a choice of commands that work on regions - this could even be auto-generated by looking at the keymap stack for commands that work on regions.
This claim seems at least suspect to me. Vim scripting isn't fun, and vim certainly isn't centred around it like emacs is, but it's possible. Usually making this claim would challenge people to solve it themselves, but I suspect that vim users care significantly less about welcoming emacs users into their environment than vice versa.
(Also, the various vim implementations in emacs are almost-but-not-quite there, to the point that I believe really experienced vim users fall into an uncanny valley.)
