i just did a return from the mun with no heat shield, all you have to do is set your apo to around 50km and let friction take over. it might take a few orbits but you will eventually get back to kerbin safely as long as your chutes can support your ship, But I will agree that heating doesnt quite work yet, i was faceing retrograde on the final descent with the pod at the top of the ship and the engine at the bottom as per normal, the engine got to around 400/450 degrees the pod reached nearly 1700 degrees when it should have been the coolest part on there