I've got a 2013 Kona Jake, which I really love, but I did have a weird shifting problem after about 2000 miles that I just couldn't solve. I took it into a local shop and they showed me that the cable had worn a small groove in the frame where it exits from the internal routing. They put a little piece of PVC liner there and it's been fine for about 500 miles since. It wouldn't surprise me if this is the problem that your LBS is referring to. The 2014 Jake the Snake has a removable plate where the cable exits. The base model 2014 Jake (like my 2013) doesn't have that, but I bet the 2015 will.

The 56cm Revel seems to me like it would be a bit small for someone 6'1". I'm just judging based on the geometry chart, but I would expect the next size up would be better for you. The Revel geometry looks very similar to the Kona Jake series geometry. I'm 5'9" and ride a 53cm Jake. I expect you could live with the 56, but it probably0 wouldn't be the best fit you could get.