> The second thing I noticed is that it uses ctrl-r as a core shortcut. Mega problem: ctrl-r is a built-in bash feature which I use every day to recall previous commands. This makes me think I can't use this tool at all.

In fairness, ctrl-a (screen default) and ctrl-b (tmux default) are also super useful readline shortcuts in bash (c-a = go to beginning of line, c-b = back one character).

EDIT: Sorry, I just realized - ctrl-r isn't a prefix, it's a shortcut, isn't it? And they have lots more? Yeah, that's ... a pretty questionable approach; it'll interfere with lots of things.