Good questions and I don't know what would be best, either. I remember about 15 or so years ago when we took our 2 sons to WDW, usually in the Fall or Winter. It was not nearly as crowded and it was much more enjoyable. I'm not sure what changed- heavy marketing to South America? Allowed more guests in? Special prices for resort stays? I know it's business so I cannot fault them for wanting more guests to come and spend $$$, yet there seems to be a point where it becomes too many guests and the experience is diminished.
I think getting rid of FP+ is a good start. It's amazing how fast the lines go during parties when there's no FP. I'm not crazy about the VQ as it is now- I think everyone should have a chance to ride, not just those who are fast on their phone. We usually end up waiting a year or two until we ride the new attractions, and we've gone to After Hours events just to have a chance to ride FoP- so guess that AH marketing ploy worked with us.
I feel designing attractions with more capacity would help a great deal, if they want to continue with the larger crowds. Perhaps a theater to attract a large audience or expand the parks but not increase capacity. They could jack up prices even more, but they better have great attractions or the cost will not be worth it.
In particular, it would be nice if they made the parks more guest 'friendly.' As we've gotten older (60s), we still love the thrill rides, but we also enjoy sitting and listening to the music and looking at what's going on. More benches and shade would be great, more water fountains for drinks, more 'atmosphere' additions such as water features or kid play areas, even more low-thrill attractions like TTA and CoP would be nice.
Lastly, they need to keep the parks up to date and not let attractions fall apart or get run down. Spaceship Earth is one of our favorite attractions, but clanking along like it's on its last legs is just disheartening. Space Mt is my favorite coaster and the rough ride adds to the thrill....but the numerous trim brakes don't. I won't even go into JII or Epcot- that's just inexcusable.
So, I don't know the solution, but I do know that we are looking at less visits and other places to vacation.