Individual leaf textures should have a subtle influence. You’re better off using texture channels on the whole bush (or areas of the bush) to achieve most of the look, and each bush is different.
You can see here that the way a material is built depends on the type of mapping, and also the maps you have / the way the geometry is built, this is one of the reasons the material editor should be a unified variable in this thought process…
Anyway, there will always be super basic presets, which would include a couple of leaf types, with almost any renderer, you would hope.
I can see that some customers just want advanced lighting and can live with a few material types (or at least that is their initial intention)