User blog comment:Cristina7/Introducing Discussions, a New Platform For Engaging Your Community/@comment-5275700-20160909212124/@comment-1370845-20160909221701

Once again, you really didn't read the post, which clearly said:

"Many have said that it's working 'just fine' but the fact of the matter is -- ﻿⁠⁠it's not﻿⁠⁠. There are some architectural decisions that were part of Forum that prohibit us from easily addressing the biggest issues: inaccessibility from Search and mobile compatibility. To truly address these we would need to rebuild it from the ground up. And so, we are -- as Discussions."

It's clear why they're doing this - for technical reasons, it's not really optional. We'll never know the extent of why this is the case, but I think the people who are paid to work on the backend of Wikia maybe know a liiiittle bit more about how it works on the backend. So because of these backend problems, they're going with a different platform to fix the errors with the current one because it's a better solution than just throwing things at the current one to make it work. And then they're saying "hey, this new feature will replace Forum eventually, how can we improve it?"

Also, I don't know what makes you think that any way Wikia proposed this would be received any differently. When Special:Forum came out, people despised it, and called it a Facebook imitator, among other things.