I believe that once the integration with Office 365 Groups service is implemented, then the API will be aligned with the Microsoft Graph and eventually subsumed by the unified API. I haven't heard of any updates in the works because of all the other progress as part of Office 365.
I am hoping that the throttle rates are reduced since it really impacts the performance of our apps.
On the subject of Yammer app dev group, if there are a lot of posts and we tag posts consistently, eventually it's possible to get a group for it based on need.