I think people are too focused on just the Shadowlands aspect of Anduin’s storyline. It also doesn’t help that many of the events that would likely traumatize a 10-15 year old boy all happened offscreen in comics, novels, etc.
Keep in mind:
- Lorewise his father was split into two men that had both disappeared for different lengths of time (1&2 years respectively)
- Onyxia was disguised in plain sight and killed several people upon revealing herself
- Anduin was kidnapped by Onyxia
- He witnessed a Scourge invasion of Stormwind
- Helplessly watched his friend/bodyguard Aerin die in an earthquake during the Cataclysm when she was crushed in a falling building
- Was held hostage by Moira during the initial succession crisis in Ironforge
- Was nearly killed by the Horde and shipwrecked alone on Pandaria for several days
- Witnessed first hand how far Garrosh had fallen and was nearly killed by him
- Witnessed the return of the Legion and was nearly killed by them in a failed assassination
- Watched in horror as Sylvanas went back on her word during The Gathering, ordered the deaths of her own people, and saw her murder Calia
- Fought in the Fourth War
- Saw visions of what N’Zoth would do
- Was captured, taken to The Maw, and forced into Zovaal’s service
- Nearly killed Kyrestia as his first act under Zovaal’s control
- Gathered all the Covenant Sigils for Zovaal, outright destroying the souls of multiple innocents in the process
All of the pre-Shadowlands stuff? That was in a ten year span. All the stuff that happened before he was king? That was before he was 17. His imprisonment in The Maw and servitude to Zovaal? That was about one year of his life in lore. Keep in mind that Anduin is a character that wished for peace, watched multiple friends/innocents die as a child, witnessed firsthand a Scourge AND Legion invasion, witnessed the Cataclysm and the widespread damage firsthand while in Dun Morogh, lost his father in a brutal manner, slowly had to learn the horrors of war firsthand, had to learn that sometimes fighting cannot be avoided, and then was imprisoned in WoW’s version of hell before being used as a weapon (and fully aware of it to boot)
Yeah, after that much messed up stuff happening from the point he was 10 years old, up until he was 21, I could totally understand him wanting to bounce for five years. Anduin’s PTSD goes far beyond the things that happened in the Shadowlands. Overall, Azeroth is actually a pretty messed up place that is in a CONSTANT state of war, be it the usual Horde/Alliance nonsense (at least up until the end of BfA), some sort of cosmic/undead horror, etc.
This world has gone from one crisis to the next, and unfortunately for Anduin, he has NEVER had a chance to properly deal with any one situation. This is a boy that became a man in a shattered, war torn world. This man has not known what true peace is since he was about nine years old.
Honestly, it’s actually a miracle that MORE people in this world aren’t forever messed up by it.