We are aware of the issue with launcher downloading getting stuck.
This issue may occur due to two different reasons:
1) High server load on days new patches are released.
We are working on improving our servers to be able to handle such workloads.
2) This issue may also occur due to network related problems.
If it prevents you from joining the game for a long time (more than 24 hours) Please, disable your antivirus and Windows firewalls, attempt to connect to the game using any VPN service or plug your internet cable directly to your PC, bypassing router - this will allow us to isolate cases where issue is outside our sphere of influence.
If this does not resolve your issue - please, send us an email at firstname.lastname@example.org titled "Launcher Stuck on Downloading - Persistent".
Please, include in the report screenshot of the issue and Launcher Log files as per this instruction.
We are working on the solution to both those instances of this issue.
Sorry for inconveniences caused.