Hello Hoodjem, I have been slowly trying to change my backhand slice to be more like Rosewall's (and more old school in general) and it has been paying off. I used to have more of a chop (similar to Federer's) and I sometimes revert to that during a match, but that is another story.
I have a lot of success with my new slice especially when returning kick serves and handling good approach shots to my one handed backhand. I usually am not able to pass someone with my slice cleanly, but I am at least making them hit a tough volley.
You work and you work and you work on a boat.