> How will all this fit into the
> programming environment of Latex3?  Will xparse and friends be rewritten
> with \type_name:args.  In fact what is the status of this aspect of
> Latex3?

Open question. We were not exactly swamped with responses to that
 \type_name:args code. We found it useful (most of the time:-) but
if it looking so strange is going to hurt acceptance of any new system
it may not be worth it, or it may (don't know:-).

On the other hand the template interface is also aimed making things
look different, but to a different target audience, someone who isn't a
tex programmer (necessarily) and they probably don't like the existing
interface, so in that case there are only advantages in having a `new

> One feature which I think would be nice is a \newargumenttype macro,
> analogous to \newcolumntype of the array package.

What new sorts of argument would you want. (this is a real question
so I understand the functionality you are asking for)

> I wait with anticipation the template packages &c.

soon, although I have to write a talk on MathML before the UKTEX meeting
on Sunday/Monday:-)