I think alot of things make this place special..
-Proximity to retail, especially carry out food places. Lunch in the park is great.
-The river views.
-The historic feel of the park, with the sculpture, the entryways, the railing along the river, etc..
-The layout of the park. How many of us have jogged around the circular sidewalk? Its just beautifully planned out... Very well thought out.
-The surrounding dense residential neighborhood that is pedestrian friendly.
-The relative lack of crime/panhandling.
-The relative GOOD upkeep of the park, someone actually trims the hedges, plants flowers, cuts the grass, etc..
Relating all of this to Hemming Plaza, one would have to increase the residential population within 5 blocks about 10 fold, rip up all those stupid pavers and put in some grass, completely rid the park of vagrants, and keep the place clean. Hemming Plaza could be Jacksonville's "Campus Martius", the downtown square that Detroit has. Add a freestanding Au Bon Pain and a band shell, hold big events there, concerts, etc... police it well, and get rid of the panhandlers and it just might work. Create DESTINATION events in Hemming, not just some guy singing bad Elvis covers for a few hours on a Friday for the benefit of the few office workers that dare venture into the park.
All in all, I guess the point Im trying to make is that the parks reflect the areas that surround it. Hemming is dying (or already dead) due to the vagrants and poor planning and the fact that downtown is a no-go zone after 5pm.