I don't care how many years I have to wait, but I want to see Morgan Stark as the new Iron Man. It would be perfect from a story perspective, opening so many doors, and it would just make more sense overall that Riri Williams.
And yes, I sad Iron Man, probably in this context should have said Iron Woman. For me, Iron Heart sounds straight up stupid.
And as a fancasting, to be honest I would go for Liana Liberato. Honestly, I saw a fan art of her in an Iron Man suit next to Tony a while ago, and the lightbulb just turned on in my mind, and I am completely unable to turn it off. She has the look: she can easily pass as a combo of Tony and Pepper. She also can act as a teenage version of phase 1 Tony. She has the arrogant teen that is not understood by the rest of humanity card. She can also play in a redemption arc similar to Tony's, although if Morgan is to become the next Iron Man her arc may not be that similar to Tony's (and to be honest the one I already have in mind isn't that similar either).
In conclusion, I consider my opinion to be 'unpopular' because everybody seems to want Riri to step up instead of Morgan. Everybody seem to want a random black girl that isn't even well liked by the comicbook readers instead of what should be the absolute most logical solution. I want to see Morgan rise and fly in the skies of NY together with Peter Parker who, now that I think of, might be a perfect mentor figure for her. And I might be exagerating here, but if this will not become a reality, and they choose to go for Riri, I might actually loose some of my respect for the MCU. Again, I'm more than likely exagerating.