I reckon one of two things has happened here:
1) Whether it was guest complaints or wanting to minimise wear and tear (probably both), the park consulted Gerstlauer over the break and found that that running the ride at the upper-end of the heat limit combined with having passenger loads in the upper-end of weight limit was making the ride rough. The ride is designed with a 650kg passenger weight average (track calculations, trains etc.) so then the easiest solution was to pop in a solution that gives operators an easy way to keep an eye on a total passenger load's weight.
2) Someone at Lloyd's or the park did a new RA over the break and decided the 650kg suggested limit could interpreted as a hard limit if an accident was to occur and decided not to take the chance. If it was Lloyd's, the two choices the park would've had was to either do as they're told or have no insurance at all and thus not be able to operate the park.
Either way, the park could do a lot more in future PR issues to quell public backlash and get ahead of it before it got really out of hand. A business their size should definitely invest in having someone on retainer who understands their business and can respond on their behalf. From the outset they needed to be transparent and explain what's going on and why.
Here's an example of great immediate transparency squashing confusion and speculation:
Also, weighing folks is unusual for a dry ride, not un-common for wet rides, if I was the park I would've released something like the following:
Acknowledges the problem, states the facts, it's transparent, and for anyone who still feels jipped there's an out. It's honestly just really hard to argue with safety too, and if everyone else globally is doing it, it shows that it's not just Adventure World being over the top.