Wouldn't this just clutter up an already crowded home screen? I like the Favourites list in the phone app as it is.

I suppose you could put Favourites as a folder on the home screen, but that would defeat the purpose since you're back to two taps for a call.

You could make the same arguments that adding browser bookmarks or more apps would clutter your home screen. I'm not suggesting that all contacts be added to the home screen, just a few that I call every day.