Feature: Logging improvements

I took a look at all the places we used `logger.info` to make sure the messages contained useful information. This is important because INFO is the default level for production apps.
I felt like the message made it sound like there was a special kind of controller called a "split controller", or some kind of special behavior. Really, the call is getting a controller executed on it, and the immediately previous log message with the same call ID says "Splitting off peer calls..."