I agree, but who knows? They probably did only a few waves to see how long the servers can last and/or so they can monitor a specific amount of people as they play.
Either way, they did send out Wave 2 ahead of schedule. They might send out more waves later today, as they did send out a "bonus" wave, but it's all up to them, obviously. Just cross your fingers.
As for me, I'm not in much of a rush knowing that I will be able to play eventually.