Colosseum was a short and easy game, and the fact that you could only save using the PC was annoying. The Purification process was so long, especially if you were aiming to purify every single shadow pokemon in that game. The best thing you could do was buy a ton of cologne to speed it up.
I didn't really get Pokemon Channel. All you did was have Pikachu watch tv and blow all your money on room decorations and new tvs. I think you were also able to go outside and force Pikachu to socialize with other Pokemon, but I forget.