it seems counter productive. he lead most of the important early victory over the protestant armies and then you have him killed before the war is even over.
Here's my old answer to a very similar question.
Because he commited high treason by starting secret peace talks with the enemy behind the emperors back.
This was the last straw, as he also had managed to make a lot of influential enemies in court and the imperial family (Habsburgians, especially the Spanish part of the family).
English is not my first language, so I apologise for any mistakes I made.