Pretty sure major outages are not normal every time there's a patch day or major release in other games. They absolutely shouldn't be given that anyone can spin up/down dynamic capacity in a cloud service provider as needed if they have designed their backend well.You waisted you own time. Don't set time aside to play on patch day in any online game. Everyone knows that. If you did it, you have none to blame but yourself.
It's definitely not normal at all in the general online services industry outside of games (e-commerce, banking, etc)