Do you have any other derailleurs to try? You can get an RD-M360, or any 7/8/9-speed derailleur, pretty inexpensively and swap it to see if you have the same behaviors, or if you can tune it out with a traditional design. The biggest challenge with swapping back and forth between a Shadow and a traditional design is the length of the cable housing and cable. The Shadow has a much more direct (and, thus, shorter) cable routing.

For me and my bikes, I ride triples with front derailleurs, so I'm not so concerned with chain drops the Shadow legitimately helps to avoid. I just have a cheap $10 Lizardskin stay protector to keep everything clean and quiet.