At the moment the IRCBot class only allows for one reply per command. It would be nice to have the option for multiline responses to let commands that need to respond with lots of information be able to format it for human readability.
Correction: sheriffbot can post multiple responses via tool.irc().post(message). The difference between: return [ "%s: Message line 1" + nick, "%s: Message line 2" + nick, ] and: tool.irc().post("%s: Message line 1" + nick) tool.irc().post("%s: Message line 2" + nick) return is probably not worth the additional interface complexity for IRCBot to support the former.
Yeah, being able to return a string is just an shortcut for simple commands.