It's hit all the Merlin parks, but I feel like Chessington in particular is really suffering from the lack of investment in anything truly new in the mid to late 2010s. Scorpion Express, Gruffalo, and Tiger Rock were all rethemes of some of the park's oldest ride systems, and while none of them were necessarily bad moves in their own right, the lack of any significant new hardware for a long time leading up to 2020 makes it feel like pretty much everything is due a major upgrade/replacement soon.
Obviously a real effort is being made to change this trend post-pandemic, with Croc Drop, the new pirate ship, Jumanji, Paw Patrol, and Minecraft all bringing brand new rides to the table, but I think Vampire's recent problems and Tiger Rock losing its gimmick really highlights how far there is still to go, and 2027 surely won't be the end of the park's growing pains.
With any luck they'll keep Vampire going a bit longer and do a good enough job of the Minecraft coaster to be able to close Vampire (be it for replacement or retrack) without a huge loss of capacity and flagship appeal, but that still leaves the question of what to do with Rattlesnake, Trail of the Kings, Tiger(less) Rock, and even Dragon's Fury before long.
I'm sure it's all doable, but whether Merlin's pockets are deep enough is another matter...