Wish list

I also share your views about namespaces.  These have caused numerous
problems for me.  It would be nice to have more of a mechanism to put
"feelers" out to the R user community when major changes are planned. 

Changes always show up in r-devel (the main CVS branch, not the
mailing list) first.  Package developers should be keeping a
relatively up to date copy of it around if they're doing things that
are likely to break.

In Hmisc and Design I reference several functions that were not exported
from packages that now use namespaces.  There is an elegant solution with
the package:::function notation, 

I'd recommend avoiding that as much as you can.  If things aren't
exported from a package, then the package writer is likely to feel
free to change them without warning.  It's much better to convince the
package writer that they missed something in their export list.

but I have been unable to use this
solution because I use one code base for all versions of R and S-Plus. 
This notation generates syntax errors in all but late versions of R.

I think it's reasonable to restrict the availability of updates to
your packages to the currently released R version.  There are reasons
why people might not be up to date (e.g. only doing upgrades at a
specific time of year), but they'll still have access via CRAN to
older versions of your package.

Compatibility with S-PLUS is a lot harder, of course.  

Duncan Murdoch