don't think sasuke should gain the ms........
he's already rejected it once........
n furthur more, this time his target is gonna be madara.........
madara has lived for almost a 100 yrs (or close to since he is one of the founding father of konoha.......)........
he's had his ems (upgraded version of ms in one way) for a long time......
he probably know everything about the ms......
n probably has ways to counter them......
so if sasuke just goes n developes a ms.........
i think madara will have him beat in no time......
in my opinion, sasuke should create a unique sharingan jutsu to defeat madara.....
that way, he's free from blindness (caused due to ms) n he gets to defeat madara....
happy ending.........