Offline support is tricky because each app needs to implement what happens in the case of data conflict. Meteor already has the groundDB package that allows for offline support in local storage. I would imagine you could implement a read only option into local storage once they release reactive graphQL.
We have some thoughts about how the new invalidation system will make offline a lot more feasible. In pub/sub based Meteor apps you would need to reload all of the data if you took too long to reconnect, in the new system you will hopefully be able to get just the diff after a much longer reconnect gap, or possible indefinitely depending on implementation details. This is because the app server doesn't need a copy of all of the client's data anymore.
