I think that the requirement for plings (!) at either end of each comment embedded directive make the parsing fairly unambiguous. The fact that it allows for 2 or more ##s to preceed the directive pleases me as I tend to use 2 most of the time. It enables me to slightly mis-define the comment card in my syntax highlighter which reduces the chance of it mis-recognising $#array and similar as the start of a comment.
I don't like the POD idea, but then I am not a fan of POD anyway. The need to use 5 lines of source-space to embed a single line of POD has always bugged me immensely.
Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
"Memory, processor, disk in that order on the hardware side. Algorithm, algoritm, algorithm on the code side." - tachyon