Marksmen Class Subgroups

Considering the differences in some marksmen versus others, Riot needs to define at least two subgroups, and tune items and design accordingly. Right now, they have very different champions (Vayne and Varus are an example of fairly divergent champions) that have a very small, very specific item pool. 4 Crit/AS, 2 Crit/AD, 4 Lifesteal, and 2 Armor Penetration items are generally all that Marksmen have at their disposal, allowing for very little divergence in item builds and play-styles.