A lot of text for a little map, isn't it? ;-) Usually, I avoid remapping for insert mode, because - typing ';' will pause for a while in case a key is pressed

A lot of text for a little map, isn't it? ;-) Usually, I avoid remapping for insert mode, because - typing ';' will pause for a while in case a key is pressed that triggers a mapping - typing the mapping when you literally mean it is often surprising. Instead, I use Ctrl+[ to escape from insert mode. Staying on the home row does not seem that important if you've just finished writing several sentences.