I like the idea. Right now, if people aren't ready, they go into action mode which prevents entering an instance. This works but can be confusing.

And to all those that say the current way is easy to understand, have you tried leading a party yet? When you ask if everyone's ready, you have to keep track of all the names and who said they were ready to find out who isn't then ask that person what's up. Having a system that tells you if someone is not ready or just not responding when make things a lot simpler on the organization side.