I have a proposal for a little but important upgrade to the Gumball.
Wish 1: What about adding the ability to repeat the last used distance while dragging (or copy dragging) with the Gumball via tapping the “R” key on the keyboard? That way, the modeler will be no longer forced to manually write long and complex numbers while dragging the object or making copies of it, ultimately saving time and reducing the chance for an input error for repetitive actions. Obviously, Rhino should remember the last distance separately from the main clipboard, because the latter is much more important for storing copied geometry.
The automatic repeating of the distance could be also combined with the following. Upon dragging an object with the Gumball and pressing the “R” key, the last used distance should appear automatically on the command line, so that any further writing of a certain number or a mathematical notation should add, deduct, divide or multiply the input number. Here are a few examples:

Gumball drag + releasing the LMB = dragging via the Gumball manually (just like what’s possible now).

Gumball drag + typing a number such like “6” + releasing the LMB = dragging via the Gumball to a manually set distance of 6 mm (again, just like what’s possible now).

Gumball drag + pressing “R” + releasing the LMB = dragging via the Gumball using the last used distance (no need to write the distance in the Command line).

Gumball drag + pressing “R” + writing “/” and “3” (without the commas) + releasing the LMB = dragging via the Gumball using the last used distance divided by 3 (example: if the last used distance was 6 mm, that command would result into moving the object by 2 mm). Note: In this case, the stored last used distance remains 6 mm even after being used to divide the distance by 3, because it could be needed for the next moving of objects by 6 mm.

Gumball drag + pressing “R” + writing “+” and “2” (without the commas) + releasing the LMB = dragging via the Gumball using the last used distance plus 2 mm extra (example: if the last used distance was 6,795 mm, that command would result into moving the object by 8,795 mm).
P.S.: The standard mathematical symbols in Rhino’s Command line are:
+ add
 subtract
* multiply
/ divide
** exponentiation (raise to the power of)
Wish 2: Add ability to lock the moving distance while clicking and holding the LMB on the tiny square of the Gumball that combines two axis (XY, YZ or XZ). Rhino only does that with the ! _Move
command. The Gumball’s square won’t be locked; instead, it moves the objects along the plane shared by two axes freely even after a fixed numerical value is being set (unlike the moving with the Gumball arrows).