That's a tough question for sure. I would say if your doing paid gigs, the blackmagic is not as good of a workflow as the other options mentioned above, ie. gh4/5 or sony a7s.
But if your doing your own projects and want the best filmic look you cannot beat blackmagic for the price. I would recommend shooting raw with the pocket though, I figure if your going to deal with all of those pitfalls you should at least let it do what it does best. So if your doing your own projects and can have a slower turn around, get all those things focal reducer, monitor, and a big camera cage and some more large memory cards and external hard drives for storage.
I own the speedbooster and sigma 18-35 and i have really enjoyed that combo on both my blackmagic pocket and my panasonic g7( gh4 baby brother). I like having the option of the shallow depth of field,( the only advantage over your panasonic 12-35) but If i were you and i was doing mostly interviews, I would recommend selling your Canon and getting a panasonic g7 which is currently on sale for $600 with lens. then you can do two camera shoots and it would match perfectly with your gh4.