My opinion and my opinion only.
With the merger ongoing, they are trying to eliminate duplicated costs and other "unnecessary" costs in order to prop up the financial reports.
Also, merging two different companies into one is a daunting task. Cedar Fair and Six Flags had many shared values but vastly different cultures. People are fighting to stay in or move up the food chain.
This can lead to upending of cultures as now there are 42 entities vs 11 or 12 as before. Cedar seems to be running the show at the top and so Six leaders are probably fearful for their immediate and long term future.
Cost cutting can be very detrimental in the long term, but seemingly beneficial in the short term. As far as Great Adventure, that park has a huge potential. But after what appears to be a very bungled 50th anniversary, I think upper management wants to start the new direction. If the Golden Kingdom ride removals do happen, it would likely lead to a huge investment in a massive expansion, most likely with a B&M GiGa. Or they might add another high capacity model and renovate Kingda Ka while removing Chang and Twister. The old Six Flags model of low capacity lower tier coasters in these massive parks will likely go to the wayside...GA should rival Canada's Wonderland and Dorney combine in attendance numbers.
But I think with all the jockeying around of the companies, the underbelly of weakness will be exposed. Communication from both chains, as a whole, has historically been weak. So let's say they are going to do this massive reno at GA, I think the park comms team might be reticent to rock the boat lest they jeopardize their positions in the company.
I haven't heard anything about Carowinds, but they rebuilt a significant portion of Hurler last year. Cyclone should be a relatively low cost machine, unless it is near the end of service life and requires costly upgrades. But, if they removed those two coasters and possibly the Drop Tower, it would open up some space. But it would make more sense to me, as an armchair enthusiast, to work with the available space where the whitewater ride was, or from a financial standpoint, remove the Borg Assimilator. That's a low capacity expensive ride to run. I don't think this will ever be a park to rival CP as a flagship, they have poured money in there and it's still a "meh" park. (Subjective, I realize). It would need resort amenities and whatnot would be difficult to justify as the park is in an industrial area and the draw in that region would gravitate towards Asheville. Subjectively, if I were going to Asheville, I'd choose Dollywood over Carowinds every time.