I know GenCon is later this year so Event Registration opens later but having it be on the Sunday of Memorial weekend is a horrible idea. That is a weekend may people travel and/or have family events. By having registration open on that Sunday you are forcing people to either risk not getting events because they have obligations that day or back out of what may be long standing traditions for them.

I know that could be said of any weekend but the probability of it affecting people goes up and you are essentially taking away people 3 day Holiday weekend.

Can't it be pushed back 1 week?

At this late stage, not likely.  There is another thread already going on this topic.

Honestly, if it is important to someone, they will find a way. It's not going to be changed and I hope it's not. Heck, I had to ask for PTO to be able to be off for it. Not everyone is off on a Sunday, but people don't worry about them. Yet you put registration on a holiday weekend and it's the end of the world...