Thinking about WU-like service I came to these conclusions:
How do you plan to receive and give money to your clients? If you want to compete with WU you need an offline places (small kiosks will do).
Say you have 1 kiosk in Madrid and 1 in Tokyo. Person A gives you 100 Euro in Madrid. You convert them to Bitcoin and make a transaction. Person B comes to your office in Tokyo and receives Yens.
1. Bitcoin works like any other ecosystem. If you stay inside it - you are good (have small Tx fee). If you convert Bitcoins to fiat - you always loose more %.
2. In the scheme above when person transfers money from Madrid to Tokyo - why do you need to use Bitcoin? You can have some cash in Madrid and some cash in Tokyo. Office A accepts money in Madrid and Office B gives money directly to client from their pile of cash.
3. Money transfer in WU costs a lot less then you think. Their profits go to office rentals, staff, salaries etc. If you wish to do you business in few countries and open 5-10 offices in different cities, hire people, pay taxes and earn money for yourself - you might end up with same fees as WU.