The information architectures of the old developer.roblox.com site vs the new create.roblox.com site are completely different, so simply swapping out the base URL will not make old links work.
I imagine deprecating this method is the most sensible course of action. It comes from a time when it linked to the actual user editable wiki so you could link to user editable pages. Without that capability I don’t see what purpose it could still serve.
Well my main use case is being able to easily open a new window for the creator docs and display documentation info on an item. I have a plugin that builds documentation based off the script itself or input and I wanted to make it intelligent and know if the item is a class, and then link it when a button is pressed. I did not know that it used to link to the old wiki, and a new method called plugin:OpenDocsPage would probably be better for long term. I know I am probably the only person who would want to use it but it will help out my workflow extremely in the long term.
We don’t make any guarantees about the structure of the create site staying exactly the same, and since you pass an opaque URI to the API it’s fundamentally prone to breaking when the information architecture changes.
I would make a feature request for what you actually want instead.