Ash also tends to catch the regional bird of every region! But I can never see Ash specializing in a single type, he just loves so many Pokemon and sees what's special in every kind.
Anyway, the episode with Gou and Tokio was phenomenal and I loved the subtle parallels between his and Satoshi/Ash's first meeting: when they both jumped to grab a Legendary Pokemon... with Ash, they both called "Lugia!" and truly caught hold of one, and they saw each other clearly, at eye level [even if Gou was upside down], whereas with Tokio, they were both wrong about what they were reaching out for, Gou called Mew, and Tokio called Celebi... and their arms blocked their view of each other, so they had to turn to even sort of see each other...
It was a really clever callback.
Another callback was Gou saying "The future is in my hand!" he said it in that phrasing in the first episode, but with a different, longer phrasing in this episode (and the difference makes sense, this was 3 years ago, and he picked it up from some song his dad was listening to)...
It makes a lot of sense why Gou was so awkward and hesitant about his friendship with Satoshi/Ash and treating it as something fragile and easily broken.
The ending really made me tear up, seeing
This was truly one of the most perfect Pokemon episodes to exist and Gou can truly carry a story all on his own! I always liked him, but I got more excited for Koharu episodes... but he really was an excellent lead here.