It seems way more plausible to me that instead of it simply being "TRANK FUCKED THE DOG" or "THE STUDIO FUCKED TRANK" (because it's usually never that easy) - looking at the rumors (reddit/collider), the reports (Hollywood Reporter/EW), the tweets (Trank/Landis/Slater), that we have a situation where:
Trank got a lot of faith placed in him and a lot of pressure placed on him.
He was told that setpieces needed to come out because they were too expensive
The resultant scramble to replace content stressed him the fuck out
The resultant stress caused him to act out
The acting out caused a lack of faith in him
The lack of faith and bad behavior meant he essentially had to be replaced
The people who had to replace him before the clock ran out couldn't come up with any ideas that were worth a shit
Those ideas weren't executed well because nobody still there had any faith left in the project
Those bad ideas, poorly executed, dragged down what good ideas were still there.
Can I quote this for visibility with the disclaimer I think you're still giving Trank a little too much credit (verbally abusing his cast members to the point of tears is still pretty fucked up and doesn't get a pass even if the studio are pricks)