When you are using an Enterprise Wiki site collection you are going to have the following problem.

The title of the Wiki pages is always linked to the actual file name of that certain page.
So for example you want to create a Wiki page with the title "Microsoft .NET Framework" you have to create that page with the exact same name.

File names with spaces are not that cool but even uglier will be the URL to that page in the browser address because of the filling up of the spaces with %20's

So in my case I want to create a page named NET.aspx. And later I want to change that title to whatever I want without touching the actual file name.

In the standard implementation it looks like that:

Browsing to the PAGE tab will give me the option to change the properties of that page.
There I'm going to change the title entry.

After saving nothing changes. What did the SharePoint developers think when they implemented that property?
Maybe the division for creating the Wiki stuff did not think of that… who knows.

So to get the use out of that property we have to manipulate the page template for the Wiki pages.
Open the Site in SharePoint 2013 designer and go to "/_catalogs/masterpage/EnterpriseWiki.aspx", open that file and look for the content place holders.

There are a lot of different content place holder IDs available to overwrite specific parts of a SharePoint page.

In this case we need the "PlaceHolderPageTitleInTitleArea". This one is used to generate the content of the title beneath the ribbon.
We just have to name the target property of the "SharePoint:ListItemProperty" control.

Save and voila the title out of that property will be displayed on the page. Now when a Wiki user wants to change that title he has just to use the obvious correct way and is going to manipulate the title property. No need to change the file name.