It seems logical but what I have noticed from the manga is that only borrowed eyes retain their power, however it cost the borrower more chakra like the case of Kakashi and Danzo.
Further to, in the case of EMS, the siblings eyes do not grant the borrower the same jutsus as the owner of the eyes because the eyes are used to activate a spiritual (Yin) power that is; it is used to grant the borrower an eternal light… I think as siblings their powers are almost the same anyway with slight differences here and there. Although gaining the eternal light grants the borrower the ability to use less chakra when using their own jutsu; it grants standing Susanoo; and opens up the ability for the user to combine or manipulate one or two of their jutsus… just like Sasuke's enton blaze release manipulation i.e. being able to manipulate his black flames over anything in attack or defence.
If Sasuke had taken only one eye, maybe he might have accessed Tsukuyomi but then again there's a down side; without both eyes he can not reach the full potential of either eye that he possesses