It is overrated, and I say that as someone who very much enjoys Nolan.

He's never at his best without his brother on scriptwriting duties (that's why TDK is far and away the best of his Batman movies), and he constantly struggles to present human feeling and emotion in a way that feels believable and real. He's so caught up in his love of crafting intricate Rube-Goldberg machines that he forgets all the other aspects of the film-maker's craft.

Don't get me wrong, I'm a fan and I'll show up for every movie he makes, just to enjoy watching how he fits all the little intricate parts together, but he doesn't even make my top five for directors. Almost everything he does, Denis Villeneuve does better.

Interstellar in particular really exposes his weaknesses, because it's a film about love being a more powerful fundamental force than gravity, and Nolan is such a fucking robot that he really doesn't know what to do with something like that. It's a movie that contains lots of really great moments, but just doesn't hang together or feel cohesive as a story. I won't knock anyone for enjoying it, but it's a clear demonstration of Nolan's flaws.