User blog comment:Brandon Rhea/Wiki domains will be changing from wikia.com to fandom.com in early 2019/@comment-27481640-20180815201737/@comment-20644-20180815202144

Great question!

Since SEO is such an important factor in this change, which wikis are converted and when will likely be decided primarily by our SEO team rather than a volunteer basis. That's my understanding for now, at least.

As for a general URL change, sure you can request that. You can even request that now - a change from wiki-to-fandom.wikia.com to wikitofandom.wikia.com. Those requests can be made at Special:Contact if you want to do that now.