I am least excited for this "dynamic lockscreen" stuff. It ain't coming to majority of WP users. It is an OS feature boasted so much, but the outcry will be louder for this stuff. It isn't coming to 512mb devices on launch and there aren't any plans yet to port it. So you are looking at either late 2014 or early 2015 when every one has this. The cool factor will be dead by then as everyone with an Android will have at least 50 apps that do this "dynamic lockscreen" or even better. Majority of WP sales from last year and early this year are from low-end 512mb devices. Most of "cool" stuff are slow or not present for these device users. They are the ones that have got us from 1.2% to 3% marketshare. If they are unhappy, MS is doing things wrong. We haven't seen any "hero devices" or any flagships in 2014 in Europe. The places that have these phones are in short-stock (if there are more than 2 places outside of USA that is)!
I was excited about things like Cortana, Cyan, dynamic lockscreen, New Skype app, New Facebook app - but that was all talked about on 2nd April - today we are sat on 5th July. It is 92 days since that chat. Nothing yet on WP. This is 25% of a year gone. If it takes MS 25-50% of a year to deliver things they talk about, they are worse than a chewing chewed 10 times, spit out 11 times and then being fed to me. So not excited at all.