He has not designated a deputy or successor, perhaps fearing that an impatient heir apparent might be a threat to him.
This is absolutely Arafat's fault! If there's major chaos in the PLO after he dies he should be blamed. Same with Castro in Cuba.
Someone who holds on to the top slot until the last is a lousy leader. A good leader tries to build a system which supports and promotes the values she or he wants to instill in the community, and then leaves it to be continued by inspired and educated successors.
BBC NEWS | World | Middle East | Q&A: What follows Arafat?