Gyuuki was smack bang in the middle of the Bijuu Bomb and he still survived, while Kurama's shown better durability feats anyway. Piercing attacks and using blunt force trauma are too different things as shown in the manga, and Madara doesn't use PS to pierce so bringing up stuff like shurikens and Chidori is pointless.
Gyuuki has fired off Bijuu Bombs almost instantly in chapter 610/611 (on my phone so can't link). I don't think Madara's ever spammed PS slashes.
Gyuuki vs giant juubi tbb is no feat yet as it barely rolled onto him then was FTGed.
Kuramas shown no tanking feats avatar did, if we consider live bijuus comparable then kurama cant be having any abnormal tanking feats in live form when even shukaku that is made of chakra infused sand had his arm cut off by a frog.
Chidori variant that cut the tail and shurikens arent piercing and neither is PS slash, its all cutting.
Yes bijuus can fire tbbs rapidly but only small ones that are no harm to PS.
Yes madara hasnt shown slash spam but is it really that hard to do? All he has to do is just swing and has 2 slashes at same time.
Another thing is that small TBB can be dodged by susanoo while slashes are much faster if they lift mountains apart simultaneously