It would be a "World Class" destination park because:
1) 306 Acres is huge. Central Park is bigger, but other than that I don't know of too many city parks in the U.S. that can compare.
2) It is historically significant. Maybe it doesn't have a very glamorous history; most tourists probably wouldn't go there for it's history alone, but it does add to the overall value.
Frankly, I can see NO REASON to develop that land... unless you're a developer who wants to make a quick buck. This is a VERY BIG opportunity for Raleigh, though, and we need to THINK BIG. If we do the right thing with that land, our children and our grandchildren and other generations will be very grateful I'm sure.