Durden put all my thoughts into words. I'm not expecting this to happen anytime soon and it's kinda worthless speculating on it. Think about it, why would a park around 10-13 years into the future use IPs that were popular in 2014? Not worth the thought
Well, until we get some intel on KidZone and future IOA additions after Kong, there's not much to speculate/discuss
nothing wrong with discussing the 3rd gate - the future tends to be most exciting with theme parks. Universal's rapid expansion is definitely something fun to pay attention to.
I do agree that the 3rd gate isn't coming until 2021 at the earliest. 2024 seems more likely - they probably plan on using the next 5-7 years to expand the options at USF/IOA, get the hotels in place, get their immersive waterpark up and running... after that, I could see more concrete plans for a 3rd gate taking place. Both parks should top 10 million in attendance each before they add a 3rd gate IMO. They don't ever need to reach the 20 million that MK will probably get to by 2021... but over 10 million would make each park fairly comfortable.
Right now, USF/IOA need to focus on rounding out each park -
some small-scale/mid level additions at both parks
nighttime show at IOA
flesh out Seuss (a dark ride, a show and a family coaster would go a long way in removing IOA's "thrill park" stigma)
fix dead areas (Toon Lagoon front area)
address Lost Continent in some way
add more to JP (as the largest island with only one major attraction, another semi-major addition - whether it be a coaster or a dark ride)
KidZone is obviously being addressed
the huge mystery plot
Shrek
Twister
Fear Factor
Hopefully, most of that is taken care of by 2020, but you never know what can happen... the 3rd gate shouldn't be added until they know for certain that they have the necessary infrastructure in place and have their 2 theme parks and 1 water park/theme park hybrid in order.
Right now, a 3rd gate is probably just blue sky