I think it's a valid point and these questions aren't always black and white. There is a certain logic to replacing underperforming attractions and utilizing that space better in a way that attracts and appeals to more guests. So, I don't think it's as simple as "replacing = bad while expansion = good" automatically.
That being said, I think there has definitely been too strong of a tendency in recent years to do replacements at WDW instead of actual expansions. In some cases, there has been some definite improvement - I would argue that SW:GE and Cosmic Rewind are both improvements over the previous things on those space and absolutely Pandora (if you want to consider that a "replacement" since most everything in Camp Minny Mickey was retained elsewhere). OTOH, there's been a number of replacements over recent years that have seemed like at best running in place so it's money being spent without clear upside - MMRR replacing GMR, FAE replacing Maelstrom, TBA replacing Splash, new CBJ show, "replacement" of the shooting galley, etc. I'm not really sold on Zootopia in ToL, IJ in Dinosaur or whatever Monster show ends up in MV3D being likely better that the current attractions either.
All the the announced things being planned/built at WDW are replacing existing attractions. I don't really have a problem with any of them in isolation, but it would have been nice if at least some new things were being built on undeveloped or shuttered land so they'd have been a true expansion without any loss. To me, I would have preferred adding a TLK ride to Africa or Moana ride to Adventureland or adding the DCA Pandora ride to DAK or putting something in Stitch or WoL first before doing the builds currenting announced. I would have put anything in DHS in the Animation building plot before doing anything with the Muppets area. I just think that WDW is underbuilt capacity wise for the attendance it draws which makes visiting the parks (most notably in DHS and DAK) unpleasant due to just not enough "stuff". They really need to work on making overall attraction capacity much more over the property and simply doing replacements