Most people use Google search for Wikipedia because it's simply easier, instead of navigating to Wikipedia and then typing in your search, just type in your sea

Most people use Google search for Wikipedia because it's simply easier, instead of navigating to Wikipedia and then typing in your search, just type in your search where you usually do. Nothing you redesign on wikipedia.org will ever change this fact, people's shortest point of access to a specific Wikipedia article will still be their browser search bar or homepage set to Google/etc. If Wikipedia's search can be improved it's simply from an accuracy standpoint. I would guess that Google employs more sophisticated spelling correction, stemming, auto completion, etc. Developing all these features to Google's level is very expensive and in that case it might make a lot of sense to just use Google's technology for the Wikipedia search.