Home Forums Fishing Flyfishing fly rod action?

I have another question for you guru fly dudes. I have a 7'9" rod and I have found I had rather have a 9' to help my keep my line off the water so I don't have to deal with 99 different current speeds at once in the mountain streams of the smokies. My question is are roll casts and aerial mends easier/more efficient to do with slower action rods.

There's a orvis store about 40 minutes from my house and I'm looking at maybe a 4wt 9' moderate action or maybe even a slow action if roll casts are made better with them.