1. No, it's a better cross fader, feels like a S9 more than the original (I used it over the weekend and the cross fader feels very fluid).
2. No, the newer version has Slip Loop.
3.. Yes the sound quality has been improved along with other upgrades to the RX2.
4. This is a wait and see, but you post this idea in the Features and suggestions forum so the engineers will see it sooner.
You won't be disappointed with the RX2, very solid and very easy to get around with the new 7" screen, very responsive.