I went out there to look at it today. It's really worn out but not completely abandoned - The main set of 3 lines is still down to dirt, so there's obviously traffic on it. The actual shape of the main line is rough but rideable. The beginner line on the main line is worn down from tabletops to just small rollers, and the gaps on middle and big were in rough shape but rideable. The wood roll-in is long gone, which made getting enough speed for the middle line very difficult and nearly impossible for the big line. On the return side of the loop, there were more jumps; a few were tracked over, but the rest were completely grown over with grass, presumably because nobody could get the speed for them, being steep-faced doubles so late in the jump line. The end of the loop was just lumps in the grass where there used to be a small tabletop, rollers, and a berm.
There was also a trail that went back into the woods that led to an extremely advanced, techy set of steep-faced dirt BMX jumps that look like they've had some very recent work done on them. That line was technically outside the boundaries of the named park but still on public land. Obviously a home-brewed thing and presumably not part of the original development.
In terms of what would need to be done to revive it: I really really think the roll-in would need to be rebuilt, probably in a different spot. A lot of dirt work, probably a complete overhaul/rebuild, would need to be done to make it more beginner- and intermediate- friendly and to make both sides of the loop viable and fun. The big berm at the back corner needs some real TLC. If a roll-in is built, it would probably take 1 weekend with a skid steer and plate compacter, and 5-10 pairs of boots to bring it back to life. Then we'd need people to ride it and maintain it long-term.