Today i am gonna explain you why sasuke will not get Perfect Susano and why it is special and unique to only Madara.
Lets talk about MS. Especially MS of madara,itachi,sasuke.
We know Itachi, Sasuke And Madara got the same abilities from MS, which is amaterasu,tsukiyomi and susano.
But tell me are they really similar?
Lets see the difference,
Itachi = Expert in genjutsu = perfect tsukiyomi.
As you can see in the above image Itachi can control time in his tsukiyomi. Now, even sasuke and madara have tsukiyomi but they cannot do what itachi can. Itachi have mastered Tsukiyomi and hence obtained perfect tsukiyomi in which time can be controlled.
This perfect tsukiyomi is only special to him and no one else can obtain it.
Kishi is a Genius, he gave the three ninjas same abilities yet they are so different.
Sasuke = expert in ninjutsu(katon) = Perfect Amaterasu.
Well as of today, it is safe to say that sasuke is currently the best katon user. He already overpowered itachi in katon .Some might say obito or madara are better but amaterasu being superior flames and since sasuke being the best amaterasu user, it is obvious he should be stated as the best katon user too.
As you saw above ,itachi's specialty is genjutsu and that is why he can use perfect tsukiyomi,
Sasuke's specialty is katon and that is why he obtained perfect amaterasu.
Only And ONLY sasuke can do this :
Sasuke combining amaterasu and susano in ms :-
In EMS :
Now only sasuke can use amaterasu to this extent, Perfect amaterasu is only special to him and nobody will obtain it.
Madara = Perfect Susano
Now i think you will understand what i meant when i said sasuke will not get PS.
Kishi have decided to give each ninja out of these 3 a specialty in certain thing.
If sasuke have perfect amaterasu, itachi have perfect tsukiyomi, then madara gets perfect susano.
Madara's use of susano is way over sasuke's or itachi's .
Sasuke and itachi's susano are no way near madara's.
Even Madara's normal susano have legs and arms, madara can hop over his susano, as if it is a summon.
he just put in more chakra,stabilized it and improved it to this extent :
Kishi is a genius.
He has decided to give each guy out of itachi,sasuke and madara a specialty.
Itachi's specialty is tsukiyomi and thats why only he can do it to that extent.
Sasuke's specialty is amaterasu and we have yet to see him using it to his full potential.
Madara's specialty is susano and that is why only he can do the perfect susano.
But Itachi had Ameterasu, so I thought Sasuke's specialty was a perfect 360 degree motion prediction, chakra vision, and memory. Just like Shisui had Tsukoyami of "Protect Konoha" which Danzo said several times after possessing the eye.