OSRS is too different for a simple change to have affected things massively.
You can't really explain a continent appearing out of nowhere, the lack of the Abbey, the Ilujanka apparently being alive and on Zeah, Glough on steroids and with seemingly no connection to Arposandra, ect.
Also, Sliske is referenced in OSRS.You never were our brightest star, Khazard. 'Vermin slaughtered like lambs'? What does that even mean?