sv and svs brakes
 

is there any advantage of having the plastic master cylinder found on the svs rather than the normal metal master cylinder

There's no difference in the master cylinder, the only difference is just the reservoir that holds the fluid.

thinking a bit to the side, is there a possability that the remote reservoir is more suseptiable to degrading the oil from the sunlight than unfaired one, considering that the unfaired one only has a small glass window while the remote one is all transparent.

By the time the fluid is brown you should have replaced it anyway, regardless.