He was great today. Never really understood why Bayern got rid of him. Pep should have taken him to City.
After his amazing first half season he fell off pretty hard, his game against Real Madrid in CL was probably one of the worst, unmotivated performances i've ever seen in an important CL game. Hoeneß also said that his agent wanted a big raise early and they weren't happy with an Interview his agent gave as well as his performances after that amazing start so selling him for a profit wasn't bad imo.
He did good at Juve last season and showed his potential at WC when he got a chance but he can also be a very frustrating player to watch, had a lot of awful games for Bayern too. Good player overall but i wouldn't want him at Barca, especially since i'd fear he wouldn't be motivated for long as a big payed sub and for a starter its not enough for me.
If i had to choose between Costa and Willian i'd still pick Costa tho but i don't think thats an option and if there was a possibility Juve would probably demand way too much, would never pay like 80M+ for a player like Costa.