As a bike commuter, I agree that the switchback concept is a little... difficult. I think most bike commuters will just proceed up either Lovejoy or Broadway itself.
It seems like an enormous expense to raise the height of the ground some 25+' over several acres. You could do it, but why? Its not very sustainable and will require thousands of dump truck loads of fill.
Then there is the issue that it creates a dark, enclosed pedestrian street immediately to its north. Also, the park should have more uses than a play field, dont you guys think?
I'd like to see better integration with the zig-zag with a building, maybe like the original ramp idea for the James Beard project, or that crazy 8 House by Bjarke Ingels:
https://www.archdaily.com/83307/8-house-big
https://www.youtube.com/watch?v=-q-e9_KFcoY