Unfortunately, your options are limited within this area. We didn ´t make the option to "translate" the node character, and we didnt take into consideration that someone would try to remove it with the node. The reason why it is indented slightly, is because there is an empty space " " before the title, which is suposed to separate the node icon with the title.
The only current workaround would be to indent the other text items with one of the following CSS styles:
margin-left - Only the numeric part of the value is used. Units (px, pt) are not parsed; pixels and points are equivalent.
text-indent - Only the numeric part of the value is used. Units (px, pt) are not parsed; pixels and points are equivalent.
You could try yo set a negative value for the .mainmenu_hasFolders class, but I am not sure it supports negative values. If not, you would have to set a slight positive value to the other items instead.