You don't want to confuse the player, it's why predkour is only on tree limbs. You don't want to make the player think they can jump somewhere they really can't. And it'd require new animations to make that happen which is money a soon to be an almost three year old game doesn't have. And frankly outside of being ready for launch, they otherwise weren't going to do it anyways as the budget they had was for the jungle. The game is based on the first film and they simply weren't going to do anything beyond that scope. It's why we don't even have the game preserve because the scope of Hunting Grounds was fitting into the style of the first film.
Doing something that requires a bit of effort is having Wolf be on model, releasing the shuriken, or fixing texture problems. But a new map with missions, geometry, textures, alternate health pickups, it's all something you'd at best get out of an expansion pack. That could never be done as free DLC.