We remember he restored the barriers, not so much his apotheosis. When he broke the Amulet of Kings, centuries of Emperors were released, temporally releasing Mundus from their obligation to keep a Dragon Blood on the throne. The remarkable difference between Martin's corronation is he was crowned Emperor of a mythic Dawn Tamriel, shifted into Oblivion by Mankar's treachery and Dagon's entry. Tamriel was characteristically Dawn's Beauty. Not the paradisal glory Mankar thought it would be.
The King of Tamriel in the Dawn is Akatosh, and in Martin's assumption to the kingship of Tamriel, he becomes Akatosh and restores Mundus. Martin Septim is the progenetor of a new Mundus; he didn't just restore the last one, but became Emperor of a new Empire, one with columns in the mythic Dawn. What might he have changed, in the spirits of his charge, as he naturalized them to the new Mundus? He lowered heaven to the people of his mythic primacy. They no longer need gods as advocates, but have won the real "Empire" of Nu-Mantia. Talos is antiquated.
Suppose you ask, "Why isn't everything different now?" I ask, "Well, what did you expect?" Not everything is going to manifest how we'd expect, or with quite the wonder Michael Kirkbride likes to envoke. Tamriel have their freedom, what becomes of that freedom is being decided by the wrong ideas...