The easiest way to ensure there's more naga stuff is to write it yourself and submit it.
Problem is, it's not really the favored fetish of any of the folks currently contributing to the game, and they already have to keep track of a dozen other variables for their scenes - plus naga and more especially taurs require either extensive rewriting of large portions of a scene to feature them, or just plain writing entirely new sex scenes for their unique bodyshapes.