The bottom line is that Lollipop is a very buggy release.
It's undercooked, in my opinion. The more I use it, the more annoyances I discover. Some more on top of the notification issues in my previous post:
* Lollipop won't use a wi-fi network which has no internet connection. This is a good idea in itself, but on some networks with a log-in page (e.g. London Underground), Lollipop won't use the connection but won't show the log-in page either. Only solution is to forget the network and connect again.
* Apps frequently being kicked out of memory and having to reload - much more than on KitKat. Particularly bad with Facebook. Even reloads the launcher sometimes.
* Lockscreen music controls - just play/pause and forward now. No back.
* When playing music, can't change the notification mode without going through the settings (since can't use the volume down button and removed from power menu)
* Can switch into guest mode from lock screen without entering passcode, permitting calls and texts by default. So somebody who nicks your phone can call as many premium rate numbers as they like, even if you have phone and SIM lock.
Some of these are pure programming bugs but most of them are simply bad design decisions, like many elements of the new notifications. Google have confused making something with good usability with making something that looks good.