I worry about my hands. I play with computers for a living, and part of the reason someone would want to hire me is that I get a job done quickly. And being able to type fast is a necessary (not sufficient) ability for that to happen.
When I was in high school I started getting horrible pain on my wrists and hands. I had to wear a wrist brace for weeks at a time. I don't know what caused it, but too much keyboard time and bad posture and good old repetitive strain injury was and is my best guess. (This was before I'd even heard of Vim. Not sure what text editor I used back then. Probably some Notepad clone, ugh.)
But then I trained myself to type more comfortably, and I haven't had any pain for years. I hold my arms at the proper angle, and I don't bend my wrists or stretch or strain my fingers. My hands bounce over the keys nowadays, on and off the home row constantly. I don't use my pinky fingers to type at all, in fact. When I need to type a q or a number or a tilde, I move my whole hand up and hit it with my ring finger. When I'm vimming, I hit ESC with my middle finger. With practice this is just as fast as keeping your hands on the home row, but I find it far more comfortable. I still do it fast enough that people remark that I'm a fast typist (though I know plenty of people who are faster).
Thus we come to Emacs. Emacs is the king of key chords. I'm OK hitting Ctrl. I pick up my hand and hit Ctrl with the side of my pinky like I'm karate-chopping it with a half-closed fist, or use my pinky and ring finger both. The Alt key I can usually reach with my thumb. But anything that requires Ctrl + Shift or to a lesser degree Alt + Shift is a killer on my hands. I don't know a good way to quickly type Ctrl + Shift + another key in a comfortable way. Caps lock remapped to another Ctrl is the solution many websites list, but that doesn't cut it for me either, it's just pinky-stretching in another direction (and what do you do when you have to hit Ctrl with your right hand?).
For some reason I'm highly amused yet slightly horrified that there really is a condition called Emacs pinky. And that Richard Stallman and other Emacs gurus have famously experienced wrist injuries due to years of using Emacs. How many people in the world can say that their favorite text editor has physically crippled them?
Even if you admit that heavy dependence on the modifier keys is necessary, some of Emacs' keybindings seem ill-chosen to me. See this quote from the Emacs tutorial:
You can use the arrow keys,but it's more efficient to keep your hands in the standard position and use the commands C-p, C-b, C-f, and C-n.
I don't know what kind of creature finds those keys more efficient than the arrow keys or pageup / pagedown, but I don't think it's a human being. (But admittedly, same goes for hjkl in Vim.) Sure, you don't have you move your hands from the home row. You just have to contort them into pretzels. Try hitting up up up down left left right quickly, then try to do the same using those keys.
Same is true of other commands.
delete-indentation, which I find myself doing a lot, is
M-^. When editing Lisp you may get to experience wonders like
Anything multi-chord is also just a little bit torturous for me. How do you execute a command more than once in Emacs? e.g. move down 3 lines? You can either type
M-3 C-n, which requires me to hit Alt with my right hand and 3 with my left, then hit Ctrl with my left and n with my right. Or you can do
C-u 3 C-n, which actually requires me to alternate hands on the modifier keys three times instead of two. This for something so ridiculously simple as moving the cursor, something I do hundreds of times a day.
This kind of crap leads you to try to hit M-3 or C-u or C-n with one hand instead of two. If I can manage to hit M-3 with my left hand, I can hit the down arrow with my right. M-3 is possible with one hand, but M-8 or M-9 would not be without dislocating a few joints. Down this path leads permanent disability.
Sometimes I toy with the idea of remapping every keybinding or nearly every keybinding in Emacs to something sane. But aside from thoughts such as "Why the heck should it be necessary for me to do this?" or "Why would this possibly be worth my time?", I'm unsure I could come up with anything better. I'd still be limited to using lots and lots of modifier keys. Emacs has had decades of refinement after all, and it's still in this sorry state.
I have tried the Vi and Vim keybindings in Emacs, and they don't work right. They don't work in all buffers, for example a SLIME REPL buffer. Even when Vim mode is working, many of the Vim commands are present, but not all. These huge, massive Emacs-customization hacks always seem to work well maybe 95% of the time for me, but text editor bindings and behaviors are really something you need to work perfectly 100% of the time. Every time Emacs does something ridiculous or one of these third-party scripts mangles my buffer, and I have to kill and reload the file, it completely breaks my stride and throws off my concentration. The text editor needs to get out of your way and let you focus on what you're doing.