Is it possible to make lib32nss-mdns a suggested dependency?

yes

first get the source of the package

apt-get source wine

then go to the extracted directory

cd wine <version>

then course to the debian directory

and edit the control file

gedit control

and move the lib32nss-mdns from depends to a new column called suggests (if its not there create one)

then save the file

then run dch -e to document your changes

then run

debuild -S -sa

to build the package and

sudo pbuilder build wine<version>.dsc

to build it in a minimal environment and to generate the .deb file

(If its too tough I ll do it and upload it to my PPA in a couple of days)

Regards

First off, this discussion only applies to the 64 bit package of 32 bit wine;
the 32 bit package should not need a 32 bit compatibility package, right?

I'm worried that making this change would break a lot of apps.
In particular, any 32 bit app that requires DNS resolution might break. See
https://bugs.launchpad.net/ubuntu/+source/ia32-libs/+bug/218097
and especially
https://bugs.launchpad.net/ubuntu/+source/ia32-libs/+bug/220377

The correct change is probably to make it a "Recommends" rather than "Suggests".
That would let you install wine without lib32nss-mdns when you know what you're doing, but arrange for it to usually be there for the average user so networking works.

The request seems to be motivated by an assumption that avahi should not be part of Ubuntu installations by default. I've fought that war, and sadly, we lost; avahi is there, and uninstalling lib32nss-mdns breaks things. Intrepid might fix this by changing /etc/nsswitch.conf, which would be great. But until then, proceed with extreme caution.