You're forgetting one point - if you get disconnected, you instantly fail a leve. Imagine you've been waiting weeks for a leve that rewards archer marks and then you fail it cuz the game crashed at the very last mob lol

That fix to retry a leve was to fix this. I'm sure they'll address this so that if you get DC'd you can retry, but if you fail, you cannot. Probably when they address the issu that you have to wait like 10 minutes to get bck on the game when DC'd ;P