Hmmm.... You know, you could also list packages you want to exclude in %packages section by prepending them with dash. Something like
%packages --nobase -apmd -atk -bluez
... etc ...
The only downside is, if package is required by something else that gets installed, it will be reincluded (while yum method will also remove the dependency).
That's why I prefer to use yum. Removes packages with dependencies. :o) But I can change our ks's to include:
%packages --nobase
....
yum remove ...
Maybe we can shorten install time. :o) David