I tried out Plasma 5 on my OpenSUSE 13.1 and it seems quite nice. The only thing is that I wouldn't like to start configuring everything from the scratch.

Is it possible to import as many settings as possible from KDE4 workspace/applications into Plasma 5 and Frameworks 5 based applications?

The groundwork is there (it's been put in as part of possible migrations) but so far few applications (given that most *applications*, as opposed to the *workspace* haven't migrated yet) have made use of it.

It is currently used by "kde4breeze" to apply some visual style consistency to the 4.x applications. A similar migration path exists for activities. For the rest, it's not been done yet.