The technical situation is as follows: We have two providers of KDE packages: one is debian unstable, the other is Santa's packages. Both rely in parts on Kubuntu's packaging, where Santa is involved as well. Historicaly over the past years, Debian's KDE packages were way behind upstream. Hence Santa started his own packaging by following upstream KDE as close as possible.
Siduction and it's users profited greatly from Santa's work and when the current transition started, he gave advice as how to handle the transition, which boiled down to waiting until things settled down. That was sound advice at the time, no matter which one of the two package streams you followed.
Along the way me and others in the team also started looking at how debian fares with respect to KDE in the transition and I transferred one of my systems from kdenext to pure debian and did a dist-upgrade, which was not easy at that point in time but worked out with lots of manual interception. Santa did not like this, as he probably thought, siduction was turning away from kdenext. I just did this in the best interest of our users.
What we have now is a situation where it is not clear if Santa will leave siduction or keep kdenext going for us. So right now, sound advice is hard to come by. What I can say is, that mixed systems (kdenext and switching to debian) will not work. If he really leaves, which I clearly do not hope, we will have to come up with a tool to convert users back to debian's packages regarding KDE.
It would be nice if Santa would chime in here and provide some clarity for users that make use of kdenext on what to expect and how to proceed. So please, as a kdenext user, have a little more patience, we will straighten the situation out as needed.