When you pair motion with screens, too much movement without proper visual synchronization (e.g. squenching, dimension) is jarring, and has resulted in the massive amounts of human projectile for which this ride is infamous (though I also strongly suspect Butterbeer with corn doesn't do too well). That's why the screens needed to be in 3D the first place. But, after some technical issues and budgeting shifts, the 3D was eventually put on an indefinite hold. I strongly suspect that with the old projectors, the 3D just wasn't cutting it. Perhaps 4K projectors with bright bulbs were simply out of the question back then. But if this was passed by Warner Bros. (Jo probably had little to no say), then I believe the quality will greatly improve the ride overall.
Patiently waiting for a POV...