I'm in the polisci program, focusing on civil wars. I did my masters here and thought about going to the states for the phd because it's academically better there. however, as i want to do policy rather than stay in academia, i decided for a shorter program here and don't regret. it was also useful, as i started working a couple of years into the programme, which i wouldn't be able to do had i been in the states.
From my experience in IOs, a phd is not going to help you in the beginning of your career - you're better off with a masters + professional experience (specially in the field). however, it can be helpful some years down the road, usually when it's too late for you to take a break from work to start a phd.
i don't really know the development program - i would say, though, that you may be able to do most of what you would like to do in the development program in the polisci program as well if you have a doubt between both.