Hi
I live in the east of the island and work in Bavaro/Punta Cana, but i live in Higuey which is not a tourist area. Crime is much higher here than living in Bavaro, but whether it is higher or lower than similar area on the north or south coast i couldnt comment.
As Chirimoya said, expats are the minority so we do mix with locals, even more so here in Higuey. I only know a handful of expats here.
You will find living in Bavaro/Punta Cana is not typically Domnican, but it is not like staying on a resort either. I personally think its a great place for people to enjoy the laid back lifestyle, beaches, weather and so on without having to completley loose all sense of civilisation (and your mind!

).