The playlist has indeed been neglected for a very long time. This always struck me as a waste. It is a feature (including lyric view) that no other DAW includes. It was only left out of one release though, and was put back in via an update of that same version.
This behaviour has always existed in the playlist. As soon as a song is seen as changed or 'dirty' it remains open. I am pretty sure it is an intended behaviour, however inconvenient.
There is a great alternative playlist program called 'midi automator' that can be used with any DAW. That same behaviour persists in it too though, as any DAW will throw up a confirmation dialogue before closing a project with percieved changes.