The issue is, if he lowers the bump, it will become literally unnoticeable.
Bump/normal mapping is not possible to currently use when any sort of more direct light is in scene. Even the weakest bump will cause terminator : /
In diffuse light, the Corona bump is fantastic, prominent, so bump mapping is great... as long as it works. With Sun, in organic shape, it does not.
You can do what I do, keep brutal turbo-smooth on (viewport-, rendertime 3+ ). Massive amount of polies, but does the job.... mostly. Sometimes it just creates smaller terminator.