while SD are smaller and get the job done and do support high capacity - CF is currently a lot faster and are more durable.
Quite the opposite. Chances are, Canon skipped CF on the 6D because it was too slow. Notwithstanding deficiencies in the camera bodies themselves, SD cards smoke
CompactFlash performance-wise. And because most flash card R&D is going into the SD side of things (because that's what nearly every camera out there is using), SD's advantage is likely to continue to grow.
The fastest CF cards, at least to the best of my ability to determine, can achieve about 160 MB/s. CF cards have not gotten any faster in nearly two years (the first 160 MB/s cards came out in January of 2012). Based on that, it seems unlikely that the CF standard will advance much past 160 MB/s, so IMO, CF should be considered an evolutionary dead end.
By contrast, the fastest SD cards currently available provide a whopping 240 MB/s write, 260 MB/s read. At that speed, if your camera can't handle continuous shooting at ten or twelve frames per second in RAW mode, the bottleneck is not the flash card. In fact, we're probably no more than one or two SD card generations away from the cards themselves being fast enough to handle full-motion full-sensor RAW video (assuming someone were crazy enough to attempt it).
Now if you're willing to change to a completely incompatible card format like CFast, you can get something with approximately the same physical form factor as CompactFlash that can outperform SD, but you won't be able to use your existing cards, and CFast cards cost a small fortune because there's not a ready supply of slower, cheaper cards to compete with them and pull prices down. And their performance benefit over SD is likely temporary unless that standard sees widespread adoption. I honestly don't expect CFast to catch on except perhaps in 4K cinema cameras, and probably not even then, given that A. SD is only about 20 MB/s shy of being able to handle uncompressed 4K RAW video at 24p and will probably cross that threshold within a single-digit number of months, and B. nobody in their right mind would write RAW video to flash when you only get about 15 minutes per 256 GB flash card. But I digress.