Developer Blizzard is currently working on four new Overwatch maps, but it’s unclear of those new arenas will ever be made available to the public. 
News comes to us via a Twitch livestream, where Jeff Kaplan and other Blizzard developers hosted a Q&A session on all things Overwatch, Ana Amari and what Season 2 will hold. 
Reddit user MattRix collated the most pertinent details to emerge from the presentation, which you can find below. 

In the next PTR patch, Mercy?s damage boost percentage is getting reverted back to what it was (instead of 50%). Discussion of the mercy damage boost happens starting at around 10:30 in the vid.
They are looking closely at how Zenyatta feels in the PTR, and will reduce his total HP to 175 if 200 is too much. The bug with Ana shots giving a friendly Zarya charge is getting fixed.
New comic with more backstory about Ana is coming very soon.
They have 4 new maps being worked on right now, but note that not all of them may see the light of day. The are working on new game modes, but the first new map (coming ?soonish?) will have a standard mode.
New skins are coming before the end of summer.
It sounded like they may want to try hero stacking again in season 2, but they didn?t actually explicitly say that For season 2 they are getting rid of coin flip (I think this was already known).
For season 2 they are also trying to reduce how long competitive matches take, which means you?ll probably have shorter attack times at the very le...