If you're referring to Toy Story Parking becoming a third gate, I have zero optimism for that. But let's say they did. How would people park hop? Either walk or take a shuttle bus. There won't be any people movers or moving walkways, and it's highly doubtful they'd expand the monorail, both for cost and the logistics of it in Anaheim's current political climate. So owning Garden Walk property in that sense would only provide a walking path between the parks while staying on Disney property, again, provided the city lets them build multiple pedestrian bridges over public roads. Too much of an optimistic fantasy in my eyes.
Secondly, if you're referring to the Eastern Gateway coming to fruition, then if Toy Story Parking stays, you'd still have to shuttle people from there to the gateway and the Garden Walk property is moot since busses will use Clementine anyway.
Thirdly, there's if BOTH happen. Then I'd see more of a benefit but still would have the park-hopping transportation issues I stated above.
If it's only your goal to blue sky with optimism in mind, enjoy. If you're being realistic, then honestly, I think pigs will fly first, but feel free to change my mind.