It's also a barrier to integration of the defined-or patch to 5.8.x, since a // where perl may be expecting either an operator or a term could mean defined-or or could mean ($_ =~ //). Without the feature, the latter would be overwhelmingly less likely to occur in real code.

Whoa... I tried really hard, but I really didn't get this at all. It's obvious you understand what you're talking about, but I think a large number of readers here (certainly most of those who would go to the Tutorials wing where this is likely to end up) won't have a clue what "the defined-or patch to 5.8" refers to, let alone what sort of distinction you're trying to make here. If this is really an important point, provide some more detail, and perhaps some code snippet(s) with comments or contrasting outputs to clarify the point. If it's not that important, then take it out, because it isn't helping.

The rest provides some useful detail (i.e. things that folks would want to know when using split // to best effect), but there is also a bit of useless detail (i.e. pedantry), which I would not commend in a "tutorial" piece.

I'd suggest you give it a day or two, then re-read it and consider how you would write it differently...