I've recently gotten very in depth on a server with some friends, and we use a custom resource pack. Right now, when the server specific pack loads, you are already in the game and susceptible to damage from anything, which can lead to mobs/fire and lava killing you before you have a chance to react. Even on a faster computer such as mine, this loading takes around 5 seconds, and is sometimes just enough for something to get at you before you can help yourself. This seems like a massive issue.