Depends on your definition of robust (e.g. how are you handling T-junctions) but in general I would agree with this, in that that some things that are NOT trivial should rightly be pushed up the art pipeline.

Good pipelines shouldn't rely on clever parser behaviour (as a general rule)

When your polygons are convex and non-planar 'simple' quickly becomes an euphemism.

You may even want to consider adjacent topology for something as 'simple' as which of two possible solutions to take, when splitting a non-planar quad into two triangles.

Triangulation is simple only when your polygons are planar and convex and aspect ratios of resulting triangles do not matter under any 2ndary circumstances. Some uses e.g. require avoiding thin, splinter-like triangles.