The reform did not outlive its king by long. Akhenaten died about 1336 BCE; within a few years the court had left Amarna, the boy king Tutankhaten had changed his name to Tutankhamun and issued a restoration decree describing the temples as fallen into ruin, and the old cults were funded again. Under Horemheb and the Ramesside kings the process became systematic: the Amarna buildings were dismantled, their small blocks reused as fill inside new pylons at Karnak, and Akhenaten was struck from the king-lists, referred to when at all as "the enemy" or "that criminal of Akhetaten". The Aten reverted to being a word for the sun's disc.
Which is why almost everything now known about the god comes from what the erasure failed to destroy. The reused blocks, the talatat, were recovered in their tens of thousands from inside later masonry and have been reassembled by computer matching into whole reliefs. The site at Amarna, abandoned rather than built over, is the best-preserved ancient Egyptian city there is. The Amarna letters, a cache of diplomatic correspondence on clay tablets found there in 1887, are a principal source for the international politics of the entire Late Bronze Age Near East, and they exist because the archive was left behind.
Modern reception has been busy, and mostly says more about the moderns. Akhenaten has been made a proto-monotheist, a proto-Christ, a pacifist, a tyrant, an aesthete and a heretic; his art, with its long skulls and soft bellies, has generated a long series of retrospective medical diagnoses, none demonstrated. The god itself has no continuous cult; there was no surviving community of Aten-worshippers after the fourteenth century BCE, and modern Kemetic revival, where it touches the Aten at all, is a twentieth-century reconstruction and not a transmission.