Hah fair point. It's like when people set their Vim leader to , or ; instead of ESC.

Also, for the single-key abbrevs I'd not use any prefix at all just like I have in my browsers "g something" googles "something", it's close to never when I need to search for a single letter (and in those cases I'd just add a space before " g" to let it parse as a literal)

These ! prefixes are nice "visually", but the ergonomics haven't been thought through

Basically, customization is the solution to such design mistakes, but lack of customizatin is another design mistake :(

Kagi does have this feature but as an opt-in per bang. It's called "Allowed Quick Bangs": https://help.kagi.com/kagi/settings/search.html#overview

The default leader key in Vim is \, which is already an easy non-shifted key.