I think the simple answer is yes. Costa wasn’t brought in to cover/replace two world-class but injury-prone wingers in Franck Ribery and Arjen Robben. He’s done that even if he may not have exactly the same statistical output as either in their heyday. What he brought to Bayern went beyond just that. Also, if one year is too soon to provide an answer to that question then five years is too long. I think those looking still waiting to make up their minds on that front would have their answer by the end of next season at the latest.