Don't forget that his Wyld Hunt involved cleansing Orr of the corruption of Zhaitan. He was never intending to get rid of Zhaitan (though he would help if he could). That was your (ours, rather) job. We killed Zhaitan and got the credit. After the "The Source of Orr" part of our PS, when Trahearne purified the source of Orr, he peaced out and went back to Fort Trinity. His job was done. We went on to slay the dragon. I really don't see how he "stole the spotlight" at all. His job is done as far as the Elder Dragons are concerned (I may eat my words though!)
If you were a sylvari alt, sure, your Wyld Hunt being to face down the dragon makes sense because they establish it from the start and yes, Trahearne doesn't take that away from you. I just really thought it was odd that no matter what your race was, he thought the only way for you to learn about your epic destiny was to go to the Pale Tree when the point of that entire story episode was to hear about his own epic destiny instead of yours. You already knew you were gearing up to fight Zhaitan simply by committing to one of the orders of Tyria dedicated to fighting him. It would have been much more flavorful and less abruptly Sylvari and Trahearne-centric for your call to arms to have come from your own race in some fashion. Maybe humans get a final echo from their six gods asking them to cleanse the Orr homeland. Maybe the norn convene in a giant moot to settle the issue of who will be The Great Hunter of Dragons. Maybe Asurans have a technomaturgical debate forum with Professor Gorr as a keynote speaker in addressing the magic loss environmental issue. Maybe Charr have the high legions come together in a tribunal to argue out whether they should help against a dragon that has mostly been affecting human lands and not them. Maybe but instead, we visit the Mother Tree, Trahearne learns that he has to nut up, take his mom's sword and lead everyone to Arah and victory. His story could have been alongside yours in a less obtrusive way if the revelation of your destiny wasn't attached at the hip to his.