Perhaps the existence of, not to mention my enjoyment of, Eternals by Gaiman and John Romita, Jr., influenced the thoughts explained below. I'm not sure.
First of all, I'm not overall sold on motion capture as the future of cinema or anything like that, to even a small extent, but I'm inclined to think the Fantastic Four movies could have been vastly better using it.
A significant problem with those movies was that while at their best moments they capture what would be generally thought of as the Stan Lee elements of the series, but seem to self-consciously avoid all of the elements that one would associate with Jack Kirby.
Even The Thing, while given the very Kirby inspired characterization, has his physicality muted in the process.
The theory is that the broad strokes look of classic four-color comics doesn't work in live action, which has some truth to it, but I think the look Zemeckis achieved could have been a nice balance between the two and allowed more leverage to portray a Four much closer to the one comic fans came to love in one of the most perfect 100+ issue runs.
Here I have to say, I think that doing the movies the way they did, without having attempted either what I suggested or some similarly bold move, the movies do a disservice to both creators. Most attempts to capture the true balance of the relationship between Lee and Kirby on Fantastic Four, acknowledge that many of the more "fantastic" elements most likely originated with Lee. Mind you, Lee gets boatloads of money and publicity from these movies and is nearly obliged to celebrate them, which must be easier when the element they do occasionally capture is the one most associated with you.
But my intentions, honestly, are less to gripe about the failings of past movies and more in hopes of influencing some in the future. I don't know what, if any, Kirby creations are in development or will be soon, but I hope those moviemakers consider something more like that for their adaptation, if not that literally, as I think the look of Kirby art is amazing and seeing something like it moving forty feet tall in front of me would be unbelievable!