EA and devs

Completely agree about create a park! If I had to guess, it's still in the dev process until the currently noted bugs are fixed. For example each of the community parks, as well as the arena would provide great locations for created parks to be skated eventually. I expect that to be in progress in some context.

For s.k.a.t.e., it's been brought up quite a lot, and there is a good chance that's on its way.

Pure guess as a 3D artist, HOM is more of a 50/50 for implementation. Subsurface stuff like bones or musculature I'm sure have been tested. But this one is the least likely of what you mentioned. The hall of meat challenges for multiplayer in Skate 3 were based on six players and a different spectation mechanic; adding more, along with cross-platform access to mobile eventually presents some issues.

Could traditional HOM be done, absolutely! But will it need a lot more time and be a lower priority? Most Likely.