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Susanoo is indeed a powerful defense and it will take a alot of damage do even start denting. But they're other ways around it.
Instead of attempting to completely break the defense, one can use
concussive damage to remove it.
The manga has shown this countless of times and I will show it all.
1.) Ay+Onoki combo enable them to built enough speed force and power to break the back bone of V2 Susanoo[
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]. Not only did it did such damage, it send Madara flying[
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]. Once crash, you have notice Madara temporary had Susanoo removed (off screen but Madara was out of commission when the Kages had a full conversation with Naruto)
2.) Tsunade, Mei, and Ay+Onoki[
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] combo KO'd Madara until a wall. Once smacked on the wall Ribcaged was removed[
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].
3.) Kabuto used Water Release on Sasuke. The Water Jutsu's concussive force removed Ribcage[
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]
4.) Guy backstabs Madara with Hirudora, the air pressure damage had Madara out of commission[
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]. We know this off screen, due to Hachibi's comment of Mokuton losing its grip[
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], thus the chakra on Wood wasn't focused anymore to do its job. (This can be a case of Mokuton users too

)
5.) Continuous Wood punches from the face[
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] had PS Sussanoo removed from Kyuubi[
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].
All it takes is a jutsu and the right physical attack to do it.