I think, that's exactly the point, why "codamedia" who opened this thread calls it "killer app". So you can't really compare this set of server behaviors to DW templates. ADDT includes can do so much more...
If you at WA had a replacement for this, you would be the kings ;-)
I usually "outsource" all my recordsets, scripts etc. to the included files (nuggets) to keep things simple. The whole site setup gets much easier to handle. Of course everyone using ADDT includes must obey certain rules or find his own workflow.
I, for example, put all these nuggets into a special folder and subfolders for my needs: "/nuggets/contactforms/" or "/nuggets/galleries/" and so on.
So once I have to redesign a function, it's very easy for me to find the right files, even if it's an old site, that I didn't touch for a long time.