Technology timeline:
Before 1000's - Cinema (Began as Chinese 'trotting horse lamps' and over time, evolved to the cinema we know today)
1910's - 3D
1940's - Hologram (Began in usage of electron microscopes)
1960's - Virtual reality & projection mapping
1970's - IMAX
1980's - 4D (This includes 7D)
Most 'new' theme park technology has been around for a while - they've just improved over time or gone through different periods of popularity. The ones between 1960 & 1990 were all introduced to the world in a theme park or it's predecessors. The ones prior to 1960 weren't originally created for theme parks or their predecessors but were later introduced in theme parks.
Based on what I wrote above, it seems likely that most future theme park technology will be introduced in a theme park-like environment first anyway.
But in terms of what could change theme parks next, this article released this month in IAAPA's Funworld Magazine, details future technological changes in theme parks (such as projection mapping, which is gaining attention with Australian theme park enthusiasts due to it's introduction in Scooby-Doo Spooky Coaster: Next Generation).
The article focuses on 3 technologies:
Unmanned aerial vehicles (drones) - 1840's (Began as incendiary balloons but over time, evolved to the 'drones' we know today)
Projection mapping - 1960's
Fireworks - 800's (Also very likely had it's debut in a predecessor of theme parks)
Probably the most 'new' implementation of technology in the article is the use of unmanned aerial vehicles in Puy du Fou's Cinéscénie:
Unmanned aerial vehicles have already been used for entertainment in Australia but not in theme parks (yet) except for marketing purposes:
You can imagine a show similar to the one above at night time theme park experiences such as Park After Dark or Carnivale but using the Cinéscénie example, imagine the possibilities of unmanned aerial vehicles at night-time theme park events such as Fright Nights & White Christmas! It would utilize the theme park's airspace for more than just fireworks and flying foxes. For a DC Comics/MW example, imagine the night the Bat-signal appears seemingly above Arkham Asylum: Shock Therapy for the 1st time.