Im anticipating an update in maybe 2-3 years. Probably some health feature additions, like a hearing aid mode that would simply amplify external sounds, or some improved noise cancellation where they could be viable as earplugs in loud environments. Live/active audio translations would be cool for conversations with international folk. Apple has room to improve, and they will always do so; otherwise they'd go the way of the airport routers and simply discontinue them.
Now im talking airpods in general, but if we are talking pro vs non-pro; i expect it to be the same situation as the iphones. A pro version with the cool new features, and a non-pro version getting the features of the older pro generation. So I could foresee a non-pro airpod 3rd gen with active noise cancellation.
I personally prefer the style of the non pro versions (especially the case) but I wish that they could somehow implement the Powerbeat Pro battery life into them, thats truly my only want out of a new generation.