Well i believe the people who work with Western will open their eyes and see they can save yearly around 2000or more dollars doing the same service with bitcoin,send money to others,the thing is that bitcoin needs to be present at all countries soo a person can buy and sell bitcoins.
bitcoin transaction is at low fees and western union charge so much fees, Most of the people not aware of the bitcoins, thats why they still using Western union. Only thing good about western its old and trustful.
WU is history for the users of bitcoin, as people who are using bitcoin will never prefer to use WU and the main reason is the higher fees that are involved in WU.