Ergonomics require that you buy some tools that allow it to be a handheld. Honestly, I don't see how it's not much different than a dslr -- especially the pocket version -- if you just pimp it out a bit. (cage, handles, etc)
The killer part, though, is the storage. Especially with the pocket, which actually has decent hand-held functionality. I mean, if the blackmagic pocket had the ability to hold lots of recorded data, and the data wasn't so large, that'd be one thing. But not the case. (there are some good battery options since it'll take external power)
Hell, I'd probably be up for a blackmagic option if only it included 50mbps encoding similar to what the gh3 offers in addition to the other modes.
As it is... I'm pretty much resigned to eliminating the pocket option due to its inability offer more robust storage without going to an external. (and then it just becomes too much.... external power, external storage, special cage, lens adapter... the add ons total up about 1500, on the cheap end)