Do you realise how the Wembley stadium looks so much like Arsenal's Emirates Stadium? The styles of each stadium looks so so similar.
They should take a look at new stadiums such as Bayern Munich's Allianz Arena or Beijing's new Olympic Stadium. Even the renovated Athens Olympic Stadium or Berlin's Olympic Stadium looks much better. As for older stadiums, have a look at Camp Nou and the San Siro.
Have they run out of ideas in making each stadium unique? I guess why the atmosphere at Man Utd's Old Trafford stadium is so different from its city rivals. Old Trafford was upgraded bit by bit, and so even after the renovations and expansion, it still managed to retain most of its character and uniqueness.