I prefer to replace Liberty Square with Cars and leave the area north of Big Thunder for another future expansion.
Those moves give us 3 new things (Cars, Villains, and the future land).
The other option seemed to be keeping LS and putting Cars in the area north of Big Thunder. That would give us 2 new things (Cars and Villains).
I think those are really the only two choices we get right now. I mean, sure, we could add more land for more things, but given what we know right now, those are the two choices.
So I value the future of that undeveloped land higher than I value what's in Liberty Square right now. Keeping in mind that the originals of these attractions still exist in Disneyland, I'm super comfortable saying that.