You know what I've realized? Gen 3 was the last time that completing the Pokedex was actually a satisfying accomplishment and even had some challenge to it.

>no online trading to get anything you want
>no transferring to auto-complete most of it
>Pokemon scattered across 5 different games
>having to play through Colosseum and XD (XD) to get Johto legendaries/starters gave them a real sense of rarity, especially Ho-oh which required some battle skills

I think I also understand why GF is moving away from the national dex being an in-game achievement, and rather focusing on the regional dex of each game. We're getting to the point where completing the national dex is just "hey transfer this and you're done" rather than actual catching, since there are too many Pokemon to fit in one gen.