Having experienced Sosua for what I would consider a lengthy enough period of time to have a valid opinion, I would expect life to go on as normal. It is usual for Expats moving into any area where tourism is high to buy into secure property, and so I expect as long as people keep to these simple and obvious guidelines then life shouldn?t be disrupted much, if at all.
Haitians and Dominicans in the Sosua and Pto Plata areas tend to be in strife with each other over things that are unimportant and never seen or known about to the average Expat or tourist. Yes there are oportunists that will grab your back, take your wallet or even threaten you with a machette if you wander down a dark alley after dark, but that is the same in most peoples neighbourhoods where ever you are.
Yes crime may well go up if the population goes up, that is natural. It should not effect anyone who isn?t involved, and if people are then they know the risks and so take the blows. From what I understand the area has taken a bit of a knock over recent years, people blame alsorts for this, dive in tourism, saturation of girls, problems with corruption, feeling unsafe and now saturation of Hatians (unwarrented as it is everywhere here in the country).
In reality every tourist hotspot has its ups and downs, years don?t run smoothly and it is difficult to keep up the demand for whatever area of income you decide to follow, that?s why the turnover is so high in tourist hotspots, people jump in expecting it to be like it was on vacation. Quite simply it isn?t.
So overall people attracted to Sosua and Cabarete know the people and the area and what is on offer and why they are there, I doubt much will be affected by more Haitians moving in.
I see absolutely no reason why torusim should be affected at all other than people continuously bringing up negative predictions and outright untruths about the aftermath of the PaP disaster, the falsity that is being passed down networks about what is happening in DR is going to do more damage than if the entire country of Haiti moved into DR. I have read about people cancelling vacations and alsorts on unfounded tales from people outside of the country (maybe picking up the exagerated claptrap reported via certain US news channels). Although it is tough and I don?t feel for these panic merchants at all in thier decision, it is affecting the numbers, not alot, but enough I expect.