I do this all the time too, but I think you're wrong about the ssh difference.

ssh doesn't see the keystroke until it's fully formed by your OS and/or window manager, so there can be no latency to the release of shift.

Thanks for telling me that! I realized that I can make the same mistakes locally with comparable frequency. Perhaps it's just that I feel annoyed when I have to backspace with latency.

Use mosh instead: http://mosh.mit.edu/

It predicts what the server will do with your input and displays the result (with an underline) until the server responds. This means typing is always at local speed even if the network is being flaky.

Happens to me even when working directly in Vim on my local system. Earlier I used to map "Tabnew" to "tabnew" and other such hacks.

Then I saw this trick that saved me considerable grief:

    noremap ; :

Now, just hit ; in normal mode to get the command line.

Same here! It's true even if it's a capital letter. Like "HEllo", "BEst REgards", "THanks"...

About "git", for me left-index, right-middle, left-middle.