My answer has to be Kennywood.
-The constant building of prototypes results in none of their newer rides being open, and while it's nice to give rarely built models a fighting chance, I feel like one park shouldn't have like 7 of them.
-Can't get their rides open on time after six months of off season (although I don't know if this happens with other parks, either way it's strange).
-The 'Auto Race' ride has been slowed down to a crawl in around 2014, causing the ride to become a tiny shell of what it used to be.
-The fact that they only seem to want to work with purely American companies can put quite a harsh limiter on what they can even add to the park. And it doesn't seem to be doing them any favours.
-New Haunt events are apparently involving alcohol like scare actors don't already deal with enough.
I'd hate to be the one to pry the Thompsons away from the place, after all, the park is fundamentally a part of their DNA.
However I'm not that bothered by the grey drabness that has descended over BPB in recent years.
I do give credit to Mandy for tidying up the park -- but at the same time, it's feeling a bit more sterile now.
Look, Icon is fun and all, but other than that, the place really has lacked major investment in many, many years. And whilst some of the park has been tidied -- other areas are looking pretty grubby.
Of course, the stipulation here would be that the Thompsons would only be replaced by an owner that is equally as passionate about the park; just someone who is willing to take a bit more risk and do things differently.
What I'd like is an Andreas Andersen type figurehead.
Someone who grew up at the place, understands all the important nuances, however isn't afraid to balance out some of the classic rides with more new, innovative attractions whilst breathing a bit more of that classic amusement park life (with a twist) into the place.
I would love to see Thorpe Park run by Compagnie des Alpes.
Look at what they've done with their parks in recent years. Walibis Belgium and Holland are being revitalised and have received cracking investments. Asterix is going from strength to strength. Bellewaerde seems to have become a hot spot for weird and wacky investments. And then look at how they've evolving Futuroscope and Walibi Rhone-Alpes. They're ticking all the right boxes.
Now imagine what they could do with Thorpe. Thorpe and Walibi Holland are similar in many ways, so they have the experience there. It has the space and flexibility in planning that it could be grown appropriately. And you can guarantee they'd manage to refresh the whole park and just make it work.
On a more practical point as well, they're a company that's not currently in the UK that I could see succeeding in the UK. I don't think it should be understated that the UK theme park industry is different to that of mainland, western, Europe, for example, so can be a tough nut to crack. But CdA are in a great position to make it work.
Obviously dropping out from the Merlin Annual Pass would affect visitor numbers. But if they played into the thrill market and their near-Heathrow location, the hit wouldn't be that hard in the mid-to-long term, if at all.
I think I will avoid the obvious answer (I think you all know what I would have said) and say Disneyland, just for the giggles. And because it would mean more attraction original IPs more tuned to the style of the medium, instead of all the attempts to "ride-ify" stories from other types of media (often manifesting as the infamous "clip show" style of dark rides that meander meaninglessly from one movie scene to another).
Hoooooo boy, unpopular opinion time: Busch Gardens Tampa/Williamsburg. SeaWorld Entertainment is moving towards a more quantity over quality ride additions program that, while not completely bad, goes against what these parks used to be. Just look at Pantheon and Iron Gwazi. Both are great rides that don't fully fit at their respective parks due to them being entirely unthemed. Pantheon especially looks extremely bad. SWE also seems to have given up on dark rides as a whole (DarCoaster pending, it's probably going to be a coaster in a box). The company has gotten rid of both parks standout non-coaster rides in recent memory (Rhino Rally and Curse of Darkastle) and took years to replace them with arguably worse rides. I can't speak for BGW, but the food at BGT is downright awful outside of a few locations. Phoenix has been left SBNO at BGT for several years and is a giant glaring eyesore. The parks are good still, but are clearly moving in a direction which I don't think is good for them.
I'd love to see Herschend buy the parks and put in the same amount of investment as Dollywood/SDC are getting.
I have to go with Kennywood. It's a park that I love so much, but I have not been thrilled with most of the decisions made in the last 15 years. I don't think Palace has been awful, but the park could be so much more. I would love to see what Herschend could do with it.