Even as a kid, I always enjiyed Hoenn and Johto over Sinnoh’s pokemon design overall. Then again I don’t care much for Kanto’s either.
Sinnoh has some cool pokemon like Rampardos, but I think Hoenn just looks has more appealing pokemon. Some Sinnoh pokemon looked a little ugly to me and I don’t know if I was playing XD but I feel like there weren’t enough Sinnoh pokemom and too many evolutions from pre existing pokemon before that time.
Maybe I also felt like Sinnoh was a little too brown and less colorful. Maybe I’m just thinking of Oreburg. I guess I always preferred tropics of Hoenn over temperate.
Although I will say Sinnoh’s legendaries are probably my favorite.
Also Sinnoh should have had more ice type pokemon