So right now my game doesn't use textures at all, only vertex colors. However many things would benefit greatly from texturing (e.g. vegetation, clothing). Adding textures means

1. Higher engine complexity
2. Much higher content creation cost

(2) is my major concern.

Anybody got any opinions/advice on this?

@lisyarus I've been working on a project for about 6 years where we only use vertex colors. Two things are very important: a consistent and distinct art style and a well thought out color palette. You should also avoid deviating from the palette if at all possible. A palette with too many colors loses its meaning.