Development Rights Sold

I am not sure how you could view it as a positive as a potential purchaser, and this is not a one size fits all process. By selling the development rights, I assume you mean sold as part of one of the town/county/state/Peconic Land Trust conservation programs. Depending upon property/location/timing/etc., the seller already has pocketed as much as $150K (or more) per acre of the land's value (or, in some cases, donated it by voluntarily relinquishing the development rights). So, while preservation was and is a laudible goal on the seller's part, a significant part of the potential market value of the property was eliminated.

The nature of the restrictions are not all the same, and you need to review carefully what the seller agreed to. In some cases, continued agricultural use is mandatory, and you need to think about whether you want to be a farmer, or be a (basically rent free) landlord to a farmer. The way this usually works (or, at least, the way it worked for my neighbor) is that the building lot on which the residence sits retains its usual rights, and the remainder is stripped of all residential development rights. More than likely, you will not be able to build or relocate any residential structure (house, pool, etc.) outside the residential building lot.

This is a long way of saying "talk to a lawyer"