I wanted to linearly scale heightfields. As a new WM user, I overlooked the scaling option of the clamp device and used the curves device instead. Trying to draw a straight line to a particular value on unlabeled axes was no joy. It would be great if curves added knots like the loft profile edit tool. Curves has a disabled button labeled "cubic spline" (version 184.108.40.206) which suggests this is on the way. If it's already present, I couldn't figure out how to activate it.
And some rudimentary axis labeling (even just ten tick marks) would be a helpful addition.
This is definitely a highly needed and good suggestion. There are many places in WM where you end up wanting to specify a curve, and a general curve editor with support for sketched or knotted splines/lines is planned and will be available in many places (for example, for specifying layout falloff shapes, etc).
If you haven't used it, Filter Forge does curves really well. They made curves their own device type that can plug into Profile inputs of noise generators and more commonly into a Tone Curve device which is the equivalent to WM's Curve device except it has a Heightfield input and a Curve input. It's great because it allows the user to manage less curves by plugging one into several tone curves. It also allows for simple curve operations to happen before plugging into a profile as seen here...
Another small request would be to make Curve Strength range go from 0-200% so curves can be exaggerated.