I believe Mechanik is also filming in Russia as well, so at least that will be an interesting location.
The thing working in Dolph's favour is that he is the one with the most power on his film sets. Defender showed that as a director he can demand more time for fx set-ups etc. The excellent choreography of the action came because Dolph wanted it and got it. A key thing that holds back someone like Sidney Furie in these movies is that he has to toe the line with the studio and keep to a very rigid time scale, that is way there wasn't too much in the way of action fx like squibs in Direct Action, compared to Defender, the same goes for Detention, which was a higher budget. Tony Hickox was saying in his Jill Rops commentary how he was despensible and had to keep to a strcit time set-up, while if Dolph requested something in the film, it would be put in. Dolph as a director can get leniancy from the producers, more time on the action. Within reason he can do what he likes because he is selling the movie. Sideny Furie doesn't sell movies. I do hope that he doesn't get a poor crew to work with as Bulgaria have notoriously lazy crews. Fingers crosseed there is good time spent on the action, and I believe there will be a motorbike chase too. Thankfully Dolph has a good DP so it should make the locations look better.