How about that, Numbers V2 is on its way out and I learn something new about it. I never realized the practicality of pasting into the Formula Bar.
However, in Numbers V3, there is a slightly clunky way to enter data into the formula editor rather than directly into the cell:
Select the Cell, Type an equals sign, hit "delete", Paste.
Not easier than Shift-Option-Command-V, but it works.