Also you have interface complexity. Adding these features requires some way to use the features, possibly including configuration options, menu items, hotkeys and so on. Prior to the Ribbon, Microsoft tried to fix this in Word by hiding all the menu items you had not used yet, so you'd never know those features were there to be used. My boss constantly asks me to remove menu items and "simplify" but he never has any answers on where he thinks users should go to access those features if they're no longer in the menu. Relevant Dilbert.