First impressions with this editor are very good.

One thing I'm not 100% sure how to do is substituions with references

so if I want to change the all the strings "foo(5, bar)" to "baz(bar).foo(5)"

with 5 and bar being arbitrary strings. How could I do that? In vim I would use a regex expression and refer to matching sections with "%s/foo(\([^,]+\), \([^)]+\))/baz(\2).foo(\1)/gc". In Kakoune it seems I might have to do some multiselect shenanigans, the regex has better escaping for my taste, but I can't match on specific selections. So I can't shuffle them arbitrarily.

I looked through the vim golf challenges and couldn't find Kakoune doing an operation like this.

mawww, do you have some screencasts of you using this editor? I would be nice to have some live demonstrations showing off useful and common usage patterns for it.