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 Tomas Sala does some pretty amazing textureless work. I have this article saved from ages ago about some of his techniques. https://web.archive.org/web/20190527040401/https://www.littlechicken.nl/oberons-court-textureless-3d-work/

Oberon's Court never got released but his next game Falconeer uses many of the same techniques.

Making textureless 3D work - Little Chicken Game Company

Oberon's Court - some insight into making a pure3D or textureless 3D game. It's not all that difficult, but it does require you to use tools differently.

Little Chicken Game Company