It would be awesome if you could make the custom race screen scale dynamically with the number of race traits and abilities.
Currently if you add more race traits or abilities to a mod than fit on the screen the relevant section becomes scroll-able unfortunately this is not indicated by anything and the scrolling is extremely slow.
So it would be nice if the custom race screen was either dynamic or even add an xml definition file for the height/width of the screen and leave it up to the modders to adjust it for their individual mod.