At first glance, one might think this transfer is bizarre. ''We already have somebody similar in Keita''. ''Are we going to throw away Keita after 2 injuries ridden season and pay big money for a similar player when Keita could still pan out great?''
In reality, when you take a moment to analyze the type of player Thiago (I always pay attention to him whenever I watch some Bundesliga games involving Bayern) is and then take a look at our team, and more specifically our midfield, you realize that he is exactly what we don't have and need.
IMHO three traits characterize Thiago:
1- He is top 3 or 5 in the world in transitioning his team from defense to attack. Smart defensive reading of the game + great vision and passing abilities means he'll intercept the ball and on his 2nd or 3rd touch the ball is already penetrating the opposition's defense.
2- He shatters the opposition's press. Very hard to put your hands on the guy because he is so agile, smart and has those burst of energy to drive the ball between two or three players. If you watched yesterday's game against City you know how much this is important. Our midfield was ripped to shreds because they couldn't deal with City press. Breaking that first line of press via smart and quick movement is key to putting your team on the front foot and enabling players like Mane, Firmino and Salah.
3- The guy is an excpetional playmaker. Watch some Thiago or even better, watch some Bayern clips on youtube and you'll notice that he creates chances from anywhere on the pitch. It doesn't matter if you are facing two compact blocs of 4 that are stationed in front of the opposition's keeper or if you're hitting a team on the counter, he will find someone with a quality pass. A bit like what Countinho used to do for us when we were struggling in front of ''park the bus style team''.
Bonus: Serial winner with Bayern which is always a good asset to have in your team especially that Milner is the only player in that squad that experience winning the PL and then lose it the year after when he was with City. We'll need someone with that ''WE GO AGAIN'' mentality. He also could be an amazing help for Keita to learn and progress as well as good competition for him.