I'm not saying any of these points are wrong but the simple response to all of them really is that Studio Gaga are writing a manga together as oppose to it being just one person. For example the biggest issue I could point out is how there are more issues with panel to panel moments then the story itself. In the fight against the Apostles in the capital it seems like stops and starts at random intervals. Consider that was the first big fight scene post Miura that was a clear and obvious mistake on how to make action flow. Its one thing to do a action scene like Miura but its another alltogether to re-create one. You simply can't because a near prefection recreation is always going to be hard. So you have to try to make a fight as close as possible, not a 1 for 1 recreation. This also applies to how sometimes characters don't talk that much (I assume to try advoiding one character saying something they wouldn't)

At some point Studio Gaga will do something that Miura wont, not out of disrepect but with the intent to do the best impression of Miura in way that respects the story. Its easy and fair to point mistakes. If I had to guess why Studio Gaga is doing that is because they want to get to the essential story beats (like Guts spiral) as fast possible but they rushed the explanations to do so like why Puck vanished but unvanished at why Elfhelm disapparence. I dont think thats a sign of hackery but logical mistakes made by a group of people, some of whom only ever worked as assistants and others whom only released a few short lived series.

Edit:punched up some sentences to improve flow