Alas, a spot for her never appeared in the metagame. Famous Magic deck brewer Conley Woods built a Mardu Ever After deck with one copy of Dragonlord Kolaghan in the main deck. That deck used the sorcery Ever After to return two creatures to the battlefield from the graveyard, in this case the Dragonlord and perhaps Linvala, the Preserver or Archangel Avacyn. It was a solid plan, but the deck never really caught on. Basically, Dragonlord Kolaghan just wasn't worth casting very often in Standard, despite popping up here and there.
Oddly enough, the format that has adopted her the most is Commander, the one in which her final ability is irrelevant. Basically, it's tribal Dragon decks that just want her to grant haste to everyone, and being a big hasty flier herself doesn't hurt.
Despite apparently not finding many homes, there is still demand for her as the Standard rotation of Dragons of Tarkir approaches. Even as her retail price has dropped to nearly $2, many buylists are paying close to $2. Plus, her price is actually trending upwards on the European Magic Card Market. There is plenty of casual appeal to this Dragonlord and she is a pretty good reanimation target, albeit not in other competitive formats. She's probably going to remain a casual hit for years to come, so don't throw her into the bulk mythic rare bin.