I fully support the legislation. Responsible owners will make the best of it. Some will also choose to have their XLs euthanised, with financial help available with that.
I agree that it won't solve the problem of this type overnight. They will remain in homes unmuzzled where family members and visitors will remain at risk, accidentally or negligently escape putting the public and pets at risk, and the wrong sort of owners will continue to behave irresponsibly and dangerously with them. Over time however, as breeding is banned, there will be less of the XL type around and available, and so the problem will at least reduce, rather than continue or escalate.
People who want that type of dog, especially for the wrong reasons, will unfortunately switch their attentions to other powerful types and breeds, and new similar types will also be developed. The problem will not end with the XL.
Like many others, I really want to see the more widespread problem of irresponsible and dangerous owners and breeders - of all types and breeds of dogs - addressed. The welfare issues for the dogs and puppies involved must be addressed in a caring society at long last. The wrong sort of owners, financially-motivated breeders and sellers-on also give all of us, and our dogs, a bad name.