Backwards compatibility isn't important until we ship 1.0 RTM so that's a non issue. We should always have Enable* flags since it's easier to understand (default values can always be set to true).  I like this solution that takes the settings object but MapHubsSettings sounds horrible. HubConfiguration sounds much better.  

More things we would add to this are things like EnablePerformanceCounters etc. Lets go with this approach and get rid of the other overloads.