if you're changing underlying functionality, you'll have to change at least some of those parameters ("show me the first IP address" of an interface might be a

if you're changing underlying functionality, you'll have to change at least some of those parameters ("show me the first IP address" of an interface might be a contrived example). So now you have the option to slightly change the parameters and keep some, but not all of the behavior, maybe even in a slightly different way or you can have a clean break and clean up the old parameter list with all its accumulated cruft and go for a designed and thought-out interface.