Not all of them were replaced...in fact, I would dare say less than half...which is still a lot of closures...and areas...that's far more closings than any of the other three parks in the last 6 years...
Millionaire replaced by TSM. Idol by Frozen sing along. Sounds Dangerous by Jedi film and Olaf M&G. Narnia replaced by Jack Sparrow replaced by Sorcerer Mickey M&G which was moved to a new spot and Minnie added. Animation Academy replaced by Launch Bay.
Citizens of Hollywood reduced but not gone. Other streetmosphere added: Green Army Men Boot Camp and temporarily, Doctor Strange.
M&Gs of Fineas, Cars, and Monsters replaced by Olaf, Chewie, Kylo, Jawas, Troopers, Minnie. Also, Mickey and pals were added to an evening dining experience.
Then, they added the Stormtroopers/Phasma Show of Force; SW Stage and Clip Show; and an evening SW projections/fireworks show. They even figured out how to reset the fireworks fast enough to have the Holiday projection/fireworks show in the same night as the SW show.
They also added a new venue: Sunset Showcase, but, I admit, that the occasional Club Villain and Dance Party is poor use of the new building.
What was not replaced was in what is now the construction zone: A ride - Backlot Tour; an attraction - LMA; one playground; one QS; and a few kiosks. The flex theater was hardly in use (it last hosted the temporary Frozen sing along before it moved to the Hyperion). The Streets of America were hardly in use (and the holiday lights were replaced by BAM!).
Every square inch of DHS which is outside the construction zone is still in use. There are no empty buildings or lots going unused. A ride, a show, a playground, and a QS being closed is not "half the park." All the other closures were replacements. And, on top of that, they added more shows.