I really like what I see, but I don't understand their reasoning for leaving out history substitution (see http://ridiculousfish.com/shell/user_doc/html/faq.htm

I really like what I see, but I don't understand their reasoning for leaving out history substitution (see http://ridiculousfish.com/shell/user_doc/html/faq.html#faq-history http://ridiculousfish.com/shell/user_doc/html/faq.html#faq-h...). Why can't a better interactive history go hand in hand with something like "sudo !!"?