Plenty of great hiking trails, I agree (those that haven't been blighted by concrete steps and steel railings) - but you can't throw a frisbee, hold a concert, or kick a football around there after work, and if you could there would be cannot signs everywhere anyway. There's no Central Park, Hyde Park, Tokyo or Stanley Park.
Kai Tak would have made a great park, open air venue and marine sports centre, but hey, no money in that now is there.. cue another shopping mall, MTR station or appalling government housing block.