You can scale points with Desc Keys, but that's usually used to do things like scale a TREE symbol based on the diameter of the tree, etc.
Other than that, you're pretty much stuck with the Styles. However, C3D labels and points actually scale with the Drawing Scale or VP Scale, and not with the Annotation Scale, so sometimes you can tweak that by modifying the Drawing Scale or VP ZOOM factor and CANNOSCALE directly. Usually not in any particularly useful way, though...
Around here, we have a couple of different "standard" sizes for point labels, and depending on the situation and current needs, we use either the bigger ones or the smaller ones. Then, I will also use the "Annotation scale" selector in the status bar to change the scale as needed. (Note that the "Annotation Scale" selector at the bottom of the screen actually changes BOTH the Annotation Scale and the Drawing/Viewport Scale, which is why C3D elements change with it. C3D elements are controlled by the Drawing or Viewport Scale, depending on whether you are in modelspace or paperspace.) So while working on a topo, I might flip that temporarily down to 1" = 10', or even 1" = 1' on occasion. Then I can read all the labels without dinking around.
Not the answer you are looking for, I'm sure...