Can I get sole legal custody of my child if my ex-spouse moves out of state?

My ex just informed me that he is moving out of state. Will the court be favorable to me having sole legal custody in this case? We currently have joint legal custody, and I am the primary physical custodian. When he moves, I feel that it would be better from a practical standpoint because he won't be around to sign paperwork to consent to any decisions that we need to make concerning our son. I have been told California doesn't usually grant sole legal custody, but I don't know in what situations they would.