I'm seeing those more and more often recently. "What's the deal with" is a slang, I don't think we should allow it.
Instead, we should be using "Who is/are?" or "What is/are?". I think these are more appropriate. Examples:
What's the deal withWho is Ichigo's Father, Isshin? What's the deal withWhat is the barrier at the end of Digimon Tamers?