I don't think it matters how the illusion is achieved; it can still be groundbreaking by theme park standards even if it's reliant on pre-existing tech (which I didn't even notice until you pointed it out). No one cares that even at opening, Haunted Mansion's peppers ghost effect was over 100 years old because it felt believable within that environment. Having a character that people actually care about, convincingly brought to life, that can roam around, is going to blow people's minds (or at least the kids).
Disney is missing the boat once again (just like with the flying dragons) by not consistently showcasing their tech with characters really care about (Beaker and Dr. Bunsen Honeydew don't quite cut it...especially as they were tied to a vehicle) and regularly within a world built for them. Free roaming R2 or Wall-e is cool, but not THIS cool. Being themed to a robot isn't nearly as impressive as bringing a biological on-screen character to life.