I feel like doing a whole E-ticket ride based on comic book characters that will be re-cast over time is a bit risky. Also, I believe Wakanda was rumored to play a big role in this (and in turn, T'Challa). With Chadwick's passing, that complicates more.
Also, I think we have to remember there's probably a pretty good chance Iron Man won't play more than a supporting role in this ride at best. This ride (if it gets built), won't open until 2025 or so the way i'm seeing things, just in time for a Secret Wars/Avengers 5. Who they put in as the "leads" of this ride will probably be a lot based on who they see the future of the MCU is with at that point and time. Then I could see the ride getting a new film sometime down the line once the current iteration is way out of date (talking 15-20 years).