Schweinsteiger gave balance to every midfield he played in between 2009 and 2016 in a way few midfielders could in the past decades, certainly not Kroos. No matter if he played with van Bommel, Khedira, Kroos, Martinez. No matter if it was a midfield 3 with an advanced CM, a 2 behind a playmaker or a 2 behind a 2nd striker. He excelled in all those roles and became the key midfielder in those sides. Kroos needs midfielders around him to balance his weaknesses while Schweinsteiger is the exact opposite. And it's even more obvious to see in the nationalteam post 2014. Even at the Euro 2016 the difference Schweinsteiger made to the team was obvious despite him being way past his peak. Sadly he became the unlucky figure in the semifinal despite overall playing surprisingly well considering his season at United.
He was the deepest midfielder next to Khedira in a 4231 and held a rather weak defense together at the World Cup in 2010 despite his midfield partner's constant gung ho runs forward, yet still had plenty of iconic moments in attack, like the counterattack against England or the run through Argentina's defense. His performances in 2010 have become a bit overshadowed by his world cup final in 2014, but 2010 was the truely outstanding tournament by him. He rose to the occasion after Ballack's injury and took over the main leadership role in the team.
In the treble winning team he seemlessly switched between being the main distributor in midfield in a 442ish formation next to Martinez/Gustavo behind Müller and a 433 with Kroos added, where Schweinsteiger played a lot off the ball.
Then there's the obvious warrior game in the world cup final 2014, which sadly turned out to be his swan song because he ruined his body playing through too many injuries during those years.