My thought exactly. Until DPRaw is adopted by ACR, C1P or DxO processing softwares, it will remain marginal for most. Maybe evolutionary dead end, but I liked the feature, when I saw a live demo of 5D IV local promo at launch.
A while ago I did see an interesting application of DP raw - someone had determined that you could, using RAWdigger, recover highlights a further one stop than normal, pushing up the dynamic range of the 5D IV even further. That would be something I'd be very interested in, but I'm not sure if anything came of it since it was nearly a year ago.
Here's a link to one article discussing it (I think there is another one out there too):
http://www.imaging-resource.com/news/2016/09/01/dual-pixel-raw-redux-forget-focus-tweaks-canons-new-tech-can-yield-an-addit
Part of me is hoping that Adobe is trying to implement this in a meaningful way before they bring DP raw functionality to their products. Not to say the 5D IV has bad DR (we all know it's great), but throw an extra stop on to it and the camera could be near class leading DR territory.
I just received my 5D MK IV, but have not had time to fool with it. As I understand it, you need to capture images at wide apertures, and can then tweak focus a very tiny amount. Unless light is dim, I generally use f/5.6 so its not really of interest. Extra DR is of no interest either, if I really need it, no camera has enough.
I tested it initially during a couple of events when I first got the camera, but ultimately I didn't think the doubled(!) file size was worth the marginal amount of additional adjustment available in post. For example, when the focus was a tiny bit off and I tried to "fix" it using the microfocus shift, the ENTIRE image got softer which didn't help me very much. The other thing is I was forgetting to turn it off and I'd end up with an entire set of 80MB raw files...that's even larger than the files out of the 5DSR...
I concluded that I'm going to be working with files of that size, I'd rather them be 50MP so I have not used DPRAW since the initial "test period" I set up.