The next step is some kind of noise injection into the metadata. There are almost certainly ways to look at who is chatting with who when. It'd be fantastic to automatically generate realistic-looking traffic to hide the normal stuff within. Plus, you'd be adding deniability to any communication you're having.

There's likely some pretty severe battery usage issues with it. If you offload the metadata fuzzing to a proxy server of some sort, then you're adding a vector to filter out that fuzz. It might be too big of a technical tradeoff to be worthwhile.