>>52966104They're alright. Playing through them now.
Most of their appeal was a short lived novelty at the time. The Pokemon available, particularly in Colosseum, weren't readily available at the time they came out, so it felt like you were catching rare exclusive Pokemon left and right. Nabbing the Johto starters and Ho Oh felt particularly special. That added a pseudo special feel to the game. Further, using them as hubs to battle in 3D was another great feature. But that novelty has worn off entirely, especially now that you can tell most of the Pokemon available are utter shitmons. I don't think these games were really meant to "last", I viewed them as Pkmn Stadium but with a short campaign as the focus.
I wouldn't call them a beacon of quality like the other anon's making them out to be, but having a limited selection and small campaign can be to its benefit. Having a billion shadow Pokemon to purify would drag the fuck on, and while the Pokemon available are largely shitty, the games balanced around them so they dont feel terrible to use. Also the music is great.