For those who spend a lot of time in the Revit Family Editor, a little golden nugget is lurking in the latest release of Revit. Prior to 8.1 if you renamed a parameter that was part of a formula(s) Revit would delete the formula(s) that used it, OUCH! This meant you had to very careful when making a change like this.
NOT ANYMORE! It's fixed! Now when you rename said parameter it gets renamed in the formula(s) automatically! Very nice!