We were aware that Google started the OTA (over the air) update of Android KitKat 4.4.2 for all Nexus devices. After installing the Android 4.4.2 update on the Nexus 4 I feel that they have not really done a lot of improvements as seeing with a naked eye and will have to go deeper to see the change.
The immediate change was the black bars i.e. the top and the bottom during screen lock and on wake-up screen. They are no more black and do not reduce the screen size. Applications are opening within seconds now and you will not experience any lag which was present earlier in Android KitKat 4.4 (as discussed by numerous users).