Shanghai's Pirates is MASSIVE. It's hard to communicate the scale. It's just enormous. Inside you're just in constant awe at the size of the thing. I'd give you a comparison at WDW for reference, but honestly there aren't any Dark Rides that are so ambitious and massive as Shanghai's Pirates. What comes closest may actually be the Dino section of Energy Adventure. Scene upon scene on that scale with an unprecedented level of detail with cutting edge tech.
It was the first time in my life that I was left in awe of the scale and technology on display.
The ride is also more than just Pirates upgraded, it's ride pacing and design down to perfection. Even if there was enough space (which there isn't) the existing building would be extremely constraining and would ultimately make an inferior experience from a ride design standpoint.
Not to mention the thing would easily cost hundreds of millions.
Instead of thinking about Shanghai, I'd be getting excited for the Battle Escape attraction at Hollywood Studios. Judging by the scale of the AT-ATs and building, we should be in for a mind blowing treat that could easily rival (and dare I say exceed) Battle for the Sunken Treasure.
That will be Disneyland and Walt Disney World's new pinnacle. Also I want to add Bob Iger has no taste. He apparently prefers the Millennium Falcon ride to Battle Escape... Well one's probably FAR easier to recreate in a lab, but still!