If anyone else has been having trouble getting their game updated, where it either hangs up on the loading bar with an animation or it is stuck on “waiting,” I have a potential little solution. In some other post I had read, I deleted some cache folder being used - that worked, but that’s not what I am discussing.
------ All you have to do is go into Task Manager and select “End task” on “Battle.net Update Agent” while your Battle.net Login client is still open. For me, it restarted the Update Agent and instantly actually started and finished the update.
Anyhow to some of you, this may be basic knowledge, that’s not who this post is for. I hope this helps until Blizzard gets a hold on this frequent issue with the client.