Why:
1. Do people hate Mario Sunshine?
2. Do people hate SM64DS?
3. Bash Mario spin-offs?
4. Complain about characters such as Petey Piranah?
5. Biggest Question : Why do people hate Mario Party?
These are the things I always hear when I hear Mario games going downhill.
These are all my answers, all in my opinion..
1. It felt like a game that starred Mario, not a Mario game. You get it? Kind of like how SMB2 was just a game that plugged in the Mario characters.. It had Mario in it, but did not feel like a Mario game.
2. I have not played SM64DS, so I can not answer this question.
3. Usually because there's so many of them (at least 7 different Mario Parties**) or the game cheats (Mario Baseball Pirahna Plant game..)
or because they hate the character selection ("<insert name of hated character here> was a poor choice!")
4. I personally hate Petey just because he was a boss in one game, suddenly Nintendo thinks they should use him as a playable character.
5. See # 3..
**Please note: I am not bashing the Mario Parties when I say that. I enjoy all of them because the mini-games and features are all different. I wouldn't play MP6 if it was the same as MP1..