I think this wold fall under the category of KDE Workspace Vision.

Many people are confused as to the difference between activities and virtual desktops. To reduce confusion and provide a visual representation of what activities are, why not use the 3d cube desktop effect for this:

Like normal, you have a desktop cube representing your four desktops. Then when you switch activities you change to a whole new cube which has a separate four desktops on the sides. Adding this visualization would make the difference between the two much clearer. Please consider adding this animation (And increase the difference between different activities by allowing unique toolbar placement and customization between activities).

In KDE 4 I use WorkFlow that helps here a lot.

For KDE Plasma 5 Ivan is working on a much improved activity switcher, which I think could replace WorkFlow.

Would this solve your problem?