Sasuke got lots of power by artificial means. CS2, Orochimaru's forbidden jutsu, and Kabuto's medical jutsu. It could be argued he got MS by artificial means since Itachi tapped it into his head. Taking Itachi's eyes, his brother's eyes will give him EMS. Yes, it is only your brother's according to Itachi.
Yes, that's very true, but each of times it was either against his will or without his knowledge.
Sasuke has never WILLINGLY taken power with no work put into it.
Although he isn't shy about taking what people give em, I don't think he would just except free power like that.
[EDIT] Also, if anything, I think he's gonna use the power to control Hachibi to gain more power, not take Itachi's rotting eyeballs.
[EDIT, again] Yea, Itachi said that taking your brothers eyes gives you EMS, but he also said many people had tried it after they saw Madara's results, but all of them had failed.