>The 'nama khandha' is easier to understand, and
>'namakkhandha/nama-kkhandha' is closer to the original texts.

In the case of separating the words into 'nama khanda' I don't think
that it is so innocent. It amounts to an editorial choice, saying
that this isn't to be read as a compound but as two separate words.
This is a very real issue in the editions I've come across so far.
Sometimes the editor has probably made the wrong choice.

Putting in the dash 'nama-kkhanda' is helpful to the reader, but
leaves open the possibiity that the editor has misanalyzed the
compound.

So I guess the answer to the original question has to do with how
certain the editor is of his/her reading. The less certain they are,
the better it perhaps is to just reproduce the manuscript without
extras.