I don't know if anyone has mentioned this previously but if the spirit of Shartan was an accurate representation of how he looked, then he was bald too. Could be just coincidence, I know, but interesting just the same. Funnily enough Shartan is someone I've always wanted to know more about too. It's odd but seeing as he was such a great elven hero, you'd think the Dalish would revere him much more and have stories to tell about him. It's almost as if he was as much an embarrassment to them, for working with humans, as he is to the Chantry.
The same Dalish who raised a human who was abandoned by her parents, and signed a treaty to aid humans during the Blight after losing their homeland to the Chantry and Orlais? I'm not seeing why you think the Dalish would view Shartan as an embarrassment, since we never hear any Dalish deride him (even the one-dimensional caricatures in "The Masked Empire" never did).
It's relegated to a codex entry by Keeper Gisharel, like most information about the Dalish. However, the Keeper addressed that the Dales was the dream of Shartan. The lack of Shartan's mention in dialogue is due to the general omission of an elven point of view on certain issues (I'd argue many issues), which I'm hoping is rectified with the elven Inquisitor and the inclusion of elven companions like Solas (as these issues were often ignored with Fenris and Merrill).
After all they go on and on about elven gods, who abandoned them and yet give only a passing reference to an honest to goodness hero who fought for the freedom of his people. Oh please let Solas know more about Shartan - that would really be a wish come true.
Perhaps the elven Inquisitor is visiting the ruins of the temple because of the apparition of Shartan, and can talk to Solas about the hero, if he shows an interest in past elven heroes? Maybe Blackwall can also tell him about Garahel.