Thomas Muller is Bayern's second best and most important player. I hope that is common knowledge. People dread the day Lewandowski or Neuer retire but I truly dread the day Muller retires, he is irreplaceable and his qualities on and off the ball will never be fully replaced.
He is the reason why Flick won a treble with Bayern as he fit his system perfectly. He is the reason why Lewa is where he is today, as the he once publicly said to start Muller. He is the reason why the system around Robbery clicked so well, as Robben said Muller is a "must".
He deserves to go out as a legend, hopefully we will see that one day because he sure is extremely underappreciated now.