The Brazilian midfielder has hailed the German league's strength and has admitted he still has his sights set on a move to Atletico Madrid
Bayern Munich and Borussia Dortmund both reached the Champions League final this season to make it an all-German affair and Diego feels German clubs will only become stronger in the years to come.
"It's a privilege to be at a Bundesliga club because, the way things are going, the German league is on its way to becoming the best footballing stage in the world," the Brazilian told Wolfsburger Allgemeine Zeitung.
The attacking midfielder then went on to discuss his future and stressed that he remains keen to make the move to Atletico Madrid, although he admitted that a transfer is by no means a certainty.
"It's true that I still want to return to Atletico. I spent a memorable year there and even won a trophy. But it's also true that I haven't signed anything with Atletico, or any other team," he added.
"It's difficult to evaluate because it's all in their hands. Atletico have to decide what they want to do, how much they want to pay, and then see if they can strike a deal. It's up to them."
Diego has a contract with Wolfsburg until June 2014.