stan-the-man wrote...
....
When copying a horizontal line of cells, and choosing Paste-Special/Reverse,
the pasted cells are pasted horizontally in REVERSE order.

I believe that this functionality enhancement would be found to be
significanly beneficial for intermediate to expert users of Excel
Spreadsheet.
....

Why? Besides, expert users already know how to reverse ranges using
formulas. Given a 1D range Rng that should be reversed in A99:#99 (# a
placeholder for the final column),

A99:
=INDEX(Rng,COLUMNS(Rng)+1-COLUMNS($A99:A99))

Fill A99 right. That's the general solution. If you knew you had an 11
cell range, you could shorten the formula to

A99:
=INDEX(Rng,COLUMNS(A99:$K99))

Fill A99 right into B99:K99.