I agree, I think the packages need a bit of work.
Just try installing kpat (the KDE solitaire game) to the KDE package that comes with Knoppix. It is going to REMOVE KDE and all existing KDE packages as part of installing this silly little game! I think what happens is it wants to upgrade some lib that is needed for all of KDE but to upgrade it it must first remove the existing lib which trashes everything that depends on it. and it doesn't know enough to restore them following the upgrade. I reported this to KDE as a bug but the response was it's a distribution problem not a KDE problem. I think the problem is actually with dpkg. I suppose I should try to report it but I haven't yet. Maybe they are already aware of it as the same problem arises with other KDE packages too.
Actually, I have had a lot of problems trying to upgrade packages and have learned to be very careful, apt-get & dpkg can turn into Freddy the package slasher real easy.