Going from the Evo to the Premier has to be the worst idea I could think of. I could spit in a snowboard shop 99% of the time it would land on a better option that the Premier. The Heritage would be better than the Premier, and the Cobra more so.
I can see the Cobra. That could be a viable option, but you can still make belly dragging carves on an SL. The flex/damp ratings are the same, but the Cobra is designed with powder in mind. The SL will be more viable in the park but will shine on groomers. You would be good with either. If you tend to ride more powder and big runs, go cobra. If you want to get more in to jumping and boxes and riding SWITCH but still want stability on bombing runs, get the SL.