I've always felt that MS was trying to get to a point where they could push all apps that are the same as those out on other platforms from behind the paywall.
They obviously felt the apps added value to Gold at least at first, even if so many disagree with that from the outside. My guess was that as soon as they felt they were offering enough value to Gold outside of app access, they would finally bring about an app store that fits in with all of the other app stores out there. The combination of more gaming features like Games With Gold and their soon to start rolling out exclusive media (those new shows they are working on producing as we speak) was probably just want they wanted to see take the place of app access as 'value' for Gold.
Add that to the fact that MS is bringing the X1 into the 'One Microsoft' fold of universal apps as we speak (developers can already build the apps) and its clear they will have to change their policy on apps behind Gold. A healthy app platform is not one that requires a membership to access. MS really want to court all app developers, so I feel its more a matter of when, not if, MS will drop the paywall and let developers do as they wish. They are probably just waiting to announce it until they have the backend service for developers done (such as expanding the current windows store developer portal for X1 apps)
I do think we could still see some apps offered free if you have Gold and either cost money outside of Gold or just not being available at all. These would be apps made exclusively for the X1, with a unique experience that would not be comparable to some mobile app or something on the pc. The ESPN app comes to mind as an example. I could see MS offering app developers support in exchange for offering an app free with Gold.