Loic says "a lot of data is maps" (in the sense of JSON objects, Python
dictionaries, etc.).  While that's true, document are mainly lists,
because order is vital.  Moreover, naming (the selection of map keys) is
implicitly the act of deciding what each thing is.

Historically, this discussion keeps spiraling through the same
neighborhoods.  One perspective, let's call it "A", is focused on
communications technology.  The other perspective ("B") is focused on
information interchange -- actual communications in all their glorious
chaos, imprecision, etc.  "A" always thinks "B" would work better if
only everything were done in response to A's insight-du-jour (some jours
are very long days indeed, viz. ASN.1).  "B" is unable to respond to
such rational argument, and is generally impatient with A's naivete.
After all, B is the suboptimal context in which the discussion must take
place -- a key point generally missed by A.  (And when that point is
*not* missed by A, A tends to throw up its hands and apply an atrocious
hack, e.g. XML Namespaces.)

Personally I think it's better to focus on B.  I have to force myself to
recognize that while B is my perspective, A's perspective is both good
and necessary to B.

Because of my perspective, I think:

* It's better to pay the cost of preserving ambiguity than to outlaw
ambiguity.  Black markets bite back.  Even more fundamentally, unclear
thinking is the only available path to clear thinking.

* It's better to pay the cost of uttering names repetitiously in exactly
the way people use them.  If that uses a bit more bandwidth, so be it.
Conserving bandwidth will not save the planet, but history demonstrates
that human confusion and ignorance can certainly lay the planet waste.
(Personally I find Loic's "save the planet" argument rather off-putting.)

* XML is terrible, but, like democracy, it's still the best available
choice because it is the most humane choice.  Like XML, democracy could
work a lot better if it weren't so profoundly stiff in its operational
details.  Will we ever have a more perfect union?  Probably.  Will we
ever have a perfect union?  Probably not, but that's OK if the story can
continue.