I'd like to add that dark side corruption also doesn't appear in the item preview feature. Basically it is what DasEmpanad said; corruption should be visible everywhere, unless user deactivates it in the game options.

Dark side corruption should be visible at the login screen. Why? Answer is simple; it not only does feel weird to see your character corrupted in every other place than the login screen, but also some people(like me) consider dark side corruption as an achievement. Achievement which is for some reason hidden in such important place. I sincerely believe that such feature is neither hard to add nor it requires that much work. I don't really have idea why it has been skipped in the first place. I know that there are far, far more important things to do(one small look at the suggestion box is enough), however if we want this game to be "perfect" at some point, we have to care about every little detail. In the end, I want to apologize for my, let's say, "imperfect" English language. I hope that what I just wrote can be understood.

Indeed, I believe that such feature should be added. It is a minor thing, but it can really improve the game feeling for some people. This is even kind of awkward when your character looks corrupted in the game and then suddenly appears to be 'normal' at the login screen.