Hi,
What will be the purpose?
“Themes” directory will disappear and the two themes will be gathered in the same place?
I don’t understand this WIP.
No, nothing was said about the themes directory being removed, just condensed things for easier management.
The purpose is listed on the description of the commit:
[wip] use more intuitive theme and dashboard directory …
The current use makes updating dashboards a bit drab as you have to commit the additions/changes to multiple areas for the themes given. This is an attempt to keep things much more simplistic with one general location to submit future applications etc…
In short, this is a means to deliver the themes with simple css and inc additions, without having to translate, add footer scripts, add additional items/applications to the dashboard, etc etc… multiple times. Now we can translate and add things directly to the dashboard without juggling adding it to multiple themes. It’s a daunting task when you have to make your changes/additions to one directory (ie; defaulted theme) and then you have to add those same changes/additions to another directory (ie; smoked theme).
Good idea 
Absolutely, it will make things much easier as we have a few new Apps about to get included in this next update. 