I'm considering upgrading because:

1. My rear derailleur has play in both the pivot at the frame connection AND the pivot at the pulley hanger to main RD body connection. Also, I've always suspected the RD was slightly bent (I got the bike slightly used), because I can't pedal backwards for a long period of time without the chain wanting to shift down on the RD/cassette. I've tried many many times, during tune-ups to correct this issue, but it always happens. It's more an annoyance than anything, and I wouldn't replace just because of this, but it will be nice if it also disappears with a replacement.

2. My front derailleur has some corrosion at the band around the frame. I also think it is a little stiffer/tighter to shift than it should be. I also don't like how close it comes to the frame when on the granny chainring (I probably can't fit more than a credit card between the frame and the derailleur body). However, I don't know if the last 2 issues will be any better with the newer model.