They have no reason to change (and I agree). When they are on Phase 12 there will be people telling their grand kids how great Phase 3 was and so on. Don't forget Marvel has failed miserably in the past, but it won't happen with Disney. Ant Man will likely be one of the lowest grossing movies in the MCU (I thought it was great - and probably their most "kid friendly" movie), but it's the first new origin movie since Cap and they have figured all of that in. They just need to be sure they don't let things become "boring" or formulaic and the Ant proved they won't do that. I enjoyed your article. I think the your likeliest scenario is the first one (which follows my logic), but if you think about it, Harley can be tested out as Iron Lad while Rhodey takes over as IM (Cheadle is one of the best actors out there, and he needs a star piece - read IM4). If the kid can't act, they'll look elsewhere. They won't let anything bring down the ship like Lucas did with Star Wars (Hayden Christenson & Jar-Jar).