Tiered pricing is ridiculous. I have nothing against it in principle but it's an unnecessary complication that will confuse guests for minimal benefit.
My point is that MK CANNOT build enough capacity to escape overcrowding. I wish it worked that way, but it doesn't. Look at the additional crowds from the relatively tame New Fantasyland. If they had built more/better, those new crowds would have been even bigger. No matter how much capacity they build, that many guests and more will flood in to fill it. You act like crowds are an independent variable that can be managed with capacity, but the two are actually codependent. If crowds were going to stay flat, increasing capacity would absolutely alleviate congestion. The problem is that crowds DON'T stay flat. When you add capacity, crowds grow, leaving you right back where you started except with more strain on walking areas and parade/fireworks viewing areas.