This was just assuming you have a huge system that needs careful regulation 
Until your bot reaches a scale that creates these problems, you will be fine with a single connection for your entire system.
Edit: the only problem I imagine smaller bots encounter is the outgoing message limit for PRIVMSG. This could easily be reached if a large channel finds it entertaining to spam a certain command for a respone. A simple safe guard would be to limit the time between sent messages, like three every second or less.