It's a shame to lose Widroe at London Stansted but with Norwegian recently being given approval to buy the airline I guess that it was rather inevitable.
As one airline leaves London Stansted another arrives as in the case of Royal Jordanian and Widroe. Its a shame but that's why the amount of airlines serving the airport always remain around the same figure.
On another note...Are Lufthansa returning to the airport at some point. There was a post a while back regarding seasonal service from Munich in addition to the Octoberfest flight's.