This might seem like a stretch, but is it possible for someone to import park editor pieces from past tony hawk games.i can make a list of possible pieces that can be added, if it'll make things easier.
Edit: here's a list of pieces i came up with.
*Low Hump
*Spine Box
*Wall Box
*Pyramid Box
*Sub Halfpipe
*Tokyo Mega
*S Bowl
*Loop
*SI MultiStep
*SI Wall Box
*Toilet QP
*Alcatraz Pool
*Clover Bowl
*Mega Rollin
*SF Comp Box
*SF QP Rail Transfer
*EMB Stage
*Alcatraz Bleachers
*Tokyo Box
*AP Walkway
*VC Planter 1-3
*Flagpole Fountain
I have more pieces from non-Tony Hawk games, but that could be put in another list