The goal of Logic 7 and PLII is to produce consistent, natural surround from stereo sources. They do pretty good. If anything I think PLII is too conservative. On some material there's pretty good surround and on others, very little. Dolby has a document on their web site with stereo material that PLII works well on.
However there may be a few situations where PLII or L7 do something artificial sounding, such as making main vocals temporarily come out of the surrounds, or ping-ponging a vocal or instrument speaker to speaker. In my experience that's extremely rare with PLII. Don't know about L7.
It's funny you mentioned Crocodile Rock. I just got the remastered stereo CD of Elton John - Don't Shoot Me, and the audio quality wasn't that good. It was somewhat flat and PLII produced relatively little surround. Likewise for the earlier albums.
By contrast the audio quality of the stereo CD Goodbye Yellow Brick Road was superb, and the SACD version of that is mind-blowing. The same producer Gus Dudgeon did both albums, and they were both done in the same recording studio. I don't understand why the huge difference.
If you have an SACD player, I strongly suggest getting the SACD of Goodbye Yellow Brick Road. IMO it's nearly good as Pink Floyd -- Dark Side of The Moon from an audio engineering standpoint. If you don't SACD, the stereo CD is vastly better from an audio and mixing standpoint than the Don't Shoot Me and earlier albums. Why the huge difference is a mystery.
