Not sure about this
I think I'll avoid this for my Nexus 4. My experience of previous updates, going back over four years and three Android phones is that Google change things because they can - from the point of view of 'look and feel'. Updates have also slowed my phones down and have removed functionality in the past. I've spent nearly two years getting used to my Nexus 4 as it is. It works fine and I don't want any changes to it.