I have noticed that the sub-menus in the themes are not defined properly. Currently working with Spirit. The drop down menu had no background. I had to add CSS to add one as there was no option to add different values for sub-menus anywhere. Most of my clients won't know how to do this and will get stuck at this point.
Would also love to have option of transitions for the sub menu that pops-up.
If I add a border between the sub menu items, the highlight and border have a tiny space in between. This is due to some global css which is applied to the ul tag making it 2em. Will be great is some attention is also paid to how sub-menu items appear as a lot of websites nowadays do require sub levels.
Also the little triangle that opens the sub-menu is totally overlapping the main menu name. It should be at a slight distance.