I'm not saying that Jeph can't do good layouts. On more than one occasion he's done something really cool looking - the introduction of Boaty in the middle of a wide blue ocean, the use of isometric viewpoint when Willow showed Hannelore around her bedroom, depicting 'movement' by having them both appear in different places around the same space. They were great.
But my big complaint is, those are rare spectacles and normally he just squeezes people into a panel in whatever order their dialogue appears, and they just move without indicating motion and end up talking to each other at strange, 70+ degree angles.
In short; Jeph has been a professional artist for over 15 years; at this point, "basic competence" shouldn't be impressive.