Yes, dolphin5 shouldn’t be necessary, just install plasma5-session and everything needed should be pulled in.
In dth2’s case it was just a coincidence that installing dolphin5 fixed his problem, I’d guess.
But some stuff like ‘desktop settings’ could not be displayed.
Hm?
What ‘desktop settings’ do you mean? The ones when you right-click on the desktop?
What happens when you do that?
Have not ever seen a problem with that, unless you reconfigure the right-click action of course. In that case, left-click on the toolbox icon in the upper-left corner to get at the settings.
Well, I created that repo months ago already, for 13.1… 
https://forums.opensuse.org/showthread.php/499607-KDE5?p=2654365#post2654365
http://lists.opensuse.org/opensuse-kde/2014-09/msg00068.html
Btw, I added a Tumbleweed repo as well a few days ago, the URL is:
http://download.opensuse.org/repositories/home:/wolfi323:/branches:/KDE:/Frameworks5/openSUSE_Tumbleweed/
This builds just against Tumbleweed, so no other additional repo is needed. You will get updates a bit later though because of that, and there might even be problems for a few days when major updates occur, as it will take a while until the updated Frameworks packages (and others I do not have in my repo) will get available in Tumbleweed (because of the additional testing. Let’s see how this goes, would be nice if you could tell me when there are issues, as I don’t use Tumbleweed myself (yet?).
I will also keep the Factory repo for now, this builds against KDE:Qt5 and KDE:Frameworks5, so you should add those two as well. You can use this with Tumbleweed as well, and you will be always completely up-to-date regarding Qt5/KF5/Plasma5 this way.
Regarding 13.2:
Upto now, the packages for 13.2 were only built against standard 13.2, not KDE:Frameworks5.
I am going to change that now though, as some packages cannot be built any more (kde-baseapps5, which includes dolphin and konqueror, in particular needs Frameworks 5.4.0 already).
So if you use that repo, please now also add KDE:Frameworks5 to your 13.2 system, otherwise you won’t be able to install/update (most of) the packages anymore because of missing dependencies.
KDE:Qt5 is not necessary at the moment, but you might want it as well to keep Qt5 updated.
AFAIK, Plasma 5.2.0 (planned to be released in January) is going depend on Qt 5.4 (unless that is delayed), so you’ll need it from that point on anyway.
You might want to give my repo a higher priority though (i.e. lower priority number), to make sure the packages are preferred. 