When scrolling down the normal view, some text is in gray and not white, so it’s hard to read. So it would be nice if we were able to change the text color 
Do you mean the upvote/comment labels and stuff like that? Titles should only be gray if the posts are read. Could perhaps add an accessibility setting that uses only pure white/pure black fonts, but I don’t think fully custom text colors would work very well with all the themes. It’d be pretty much impossible to ensure that the colors are legible on all kinds of backgrounds.
I get where you’re going. However, user customization is always a plus to the end user.
I think having the ability to change the color and grayscale as a separate option from themes is fine. And if they toggle a different theme it can reset the color just in case of white on white.
