Anyone coming from wow would have a bit of anxiety regarding an expansion launch that's for sure but as I've been through each of XIV's expansion launches, they don't even come close to any of the disasters wow has had when it comes to launch days. XIV servers on early access launch almost never crash and if they do aren't down for much time. The biggest hiccup they ever had was with Stormblood launch and the whole "Raubahn EX" stuff which wasn't even all that bad, you just had to wait a hot minute to get into a solo instance. Like others have said Shadowbringers launch was even better than all the others, almost nothing went wrong. I believe they will be prepared as they can be even with the big influx of wow players recently. I have hope