I completely agree: there is a big middle ground between the simplest SLD and the monstrous one currently uncovered by a tool (neither open source nor proprietary, as far as I know). In a typical GIS scenario we see the GIS operator (as such, not a programmer able to hand-code the SLD) creating important thematic symbolizations for data he/she has built. Every commercial GIS software today can do that (ArcGis, MicroStation, AutoCAD, Geomedia, etc.) but there's no way to export that simbolization in SLD.
We found this: http://arcmap2sld.geoinform.fh-mainz.de/ArcMap2SLDConverter_Eng.htm
The interesting idea is that you can use all the power and user-friendlyness of such a rich tool like ArcGis and having its thematism converted in an SLD file; of course that conversion tool is far from complete 
If I can say, I think it was a pity to have several very basic SLD editors open source (MapBuilder, maybe Geoserver is creating one too), even web based (isn't it a nonsense to create such a complex GUI tool in a web interface?), and not developing a single robust and complete tool, like uDig could became (there are not many fast improvements in this direction, it seems to me).
Only my 1 cent.
Cheers,
Fabio
-----Messaggio originale-----
Da: Andrea Aime [mailto:aaime@anonymised.com]
Inviato: mercoledì 21 febbraio 2007 15.41
A: Fabio Da Soghe
Cc: 'geoserver-users@lists.sourceforge.net'; User-friendly
Desktop Internet GIS
Oggetto: Re: [Geoserver-users] R: SLD editorFabio Da Soghe ha scritto:
> Indeed this seems very odd to me: I was sure there would have been
> plenty of open source utility to edit visually an SLD style, but
> there's none today.
>
> In my company we are in great difficult for this reason:
programmers
> are the only capable of editing an SLD document with good
proficiency
> but they are busy developing the application that will use
it, and the
> GIS people has not all the XML and WMS knowledge needed to
create more
> then the simplest style.
>
> Maybe SLD is not so much used today?The only systems I know using SLD are those Geotools based,
and DeeGree.
uDig uses SLD under covers, whilst unfortunately Geoserver
does not have an SLD editor. To be fair, uDig covers the most
common cases, and makes you revert to SLD hand coding for the
most complex issues.The WMS spec did not force people to use SLD, and given the
complexity of the specification, most just flew away.I agree an SLD editor is very much needed, yet:
* basic cases are handled by uDig. The only pity is that it's hard to
build a complex layered style with different "simple" styles for
different scale levels, and hard to apply filters (the CQL module
would allow for quick and intutive filter spec input).
* more complex ones tend to turn into scripts anyways. On the
Sigma demo we do have an SLD that is around 2000 lines,
any graphical
editor allowing to play with such a best would not probably be much
simpler than coding XML directly...I guess the middle ground is the interesting territory that's
not covered, that is, scales and filters with relatively
static symbolizers.
uDig could evolve to cover it.Cheers
Andrea