Blizzard has gone ahead and added in a server browser as part of the latest PTR update for Overwatch
. This addition allows you to customize a huge number of variables and play the game with your friends, those you invite, or even with the general public.
This PTR update also includes the Capture the Flag game mode, first introduced in the ongoing Capture the Rooster event in the non-PTR release of Overwatch. This update also includes the start of the re-balancing of Bastion, a change to Eichenwalde, and plenty of other changes/balancing.
The current list of changes can be found here
. The PTR is optional and will probably have a number of changes between now and the public release of the next major patch.