It is great that your contact list can immediately sync up with your Google and Facebook accounts, downloading and collecting a huge host of valuable information that is a huge time saver. There are drawbacks though. For anal retentive people like myself, it can quickly become a quagmire to keep organized. The good news is that there is no real good reason to work at keeping it organized since the universal search works so well. Still, it bugs me a little bit.
Part of that is the inability to remove Facebook friends from your contact list. I can understand why the idea that I would want to might have escaped the plans for the functionality, after all I am supposed to have friended/accepted their friend request for a reason. Still, I think we all know that with the rise of social networks there has been a prevalence for people for them to not mirror their "real life" counterparts. End result? A number of friends that you would rather not be cluttering up the contact list on your phone. For syncing purposes, perhaps there was just no good way to keep the Pre's contact list and your Facebook profile in communication without restricting your ability to remove contacts, but if so again I think it should be an option to disable if you so choose.
The other part of it is that for some reason you cannot simply sweep away profiles that you want to delete like you can with notification balloons or text message conversations. Instead you have to click on the contact and from inside go to the menu and delete it. That is a few unnecessary steps and really drags down the ability to quickly trim a contact list.