I actually think this is a bit confusing (and if multiple OT reasons are currently being displayed, I don't know that they should be). The purpose of the close banner is to tell the OP what's wrong with their question so they can improve it. If you tell them it's too broad, okay, they can narrow the scope. If it's too vague, they can explain themselves further. If you tell them it's too broad AND vague AND opinion based.... You're just confusing them. If closevoters can't agree as to the reason why the question should be closed, that (in my experience) means the question isn't as cut-and-dry as most are. If a question is clearly opinion-based, all closevoters will vote for that.
Hmm, I don't know if I'm making sense. I guess I'm just saying that the purpose of the close banner is to point the user in the right direction to fix their post, and if you tell them to fix a million things at once they're just going to get confused. Chances are if they really sit down and try and correct their post to fix errors mentioned in one close reason, they're going to have made it an acceptable question in general. No additional close banners necessary.