I'm running an up to date arch linux installation and ark is currently my archiver of choice. I am using the enlightenment WM/DE and thunar as my primary file manager. I do not have any other window manager or DE installed, but I do have another file manager (enlightenment's file manager) for which the drag and drop also does not work.

To clarify I can't drag and drop files from Ark to the other file managers, but I can drag and drop files from the file managers to Ark which I find a bit odd.

Just to verify that this isn't caused by KDE specific functionality, could you test using Dolphin?

It works fine with dolphin.

Could you try performing the drag and drop into a text editor or similar? I suspect the drag and drop operation is using zip/tar formatted URLs, which only KDE applications will be able to handle.

Does not work with:

Thunar
Sublime-Text Editor 2
Terminator
Audacious
Firefox
Enlightenment File Manager/Desktop
Krita (KDE application, I also tried the intergrated file browser in krita, didn't work with that either)
QT Creator
Google Chrome (Beta)
Audacity
CMPlayer (QT application)
7ZipFM

Didn't find anything else it works with, although Konqueror might be something to try on your end (Can you replicate the issue on your end with thunar?)

It works with Konqueror as expected - Dolphin and Konqueror share code in this regard. I can confirm the behaviour you see with Thunar.
Krusader also accepts the drag and drop events, but it seems to do nothing with them.

I'm afraid i'm not sure why this doesn't work - and are not aware of any applications which could be used to verify my initial suspicions.

Any news on this? I must admit that I find Ark to be the nicest archive manager ever made as far as functionality and interface goes, I really hate that I can't use it outside of kde (because I really, really don't feel the same about Dolphin)

From a quick view (I personally use neither) ark carries a special mimetype, which apparently only the dolphin view can handle. Likewise, fileroller will most likely only work w/ nautilus (but maybe thunar as well)

The reason is how Ark and DnD work in general - and apparently no protocol for this.
Ark (*no*! sane extractor) does not extract the archive when you open it, but just displays the indexed content.
So when you drag a "file", that file does not actually exist, but is just a reference to some entry inside an archive.
It is then not ark, but the other application which will have to announce "I can make use of this" and extract that particular file out of the archive (while it could invoke ark for that job

When you drag sth. like "ark://file@archive.zip" (purely made up, I don't know what the mime/url looks like) into Thunar, it sees "errrr... WTF??" and says "no. i cannot handle this"

There are two possible solutions to this:
a) make ark extract the file(s) to a temporary position whenever you start and drag that actual file URI
b) make thunar support the ark mime type

(a) is silly because it implies major overhead when cancelling a DnD (+ more trouble on ro filesystems)
=> File a bug against Thunar and/or pitch for a common protocol on this.