See, the problem with this thread hasn't been his opinion. He's perfectly allowed to have whatever opinion he wants. I don't like Gears of War (shame since I bought the first), yet that's one of the most highly respected franchises of this generation. It's my opinion. Happens.
The problem is that he doesn't seem to understand what he's forming his opinions about. It's like saying the Cincinnati Bengals are a terrible football team this year because they aren't scoring any home runs. While the conclusion may be true - that they're a lousy team this year - the reason for believing that is terribly wrong.
You can't form an accurate opinion on something unless you understand what you're supposed to be expecting.
Metroid Prime isn't aimed at the typical FPS fan. It's not a FPS. You can't play expecting a typical FPS experience.
Zelda isn't an RPG; it's an action-adventure, maybe partially adventure-RPG. If you play expecting gameplay similar to Dark Cloud or Elder Scrolls, you're going to be disappointed.
Smash Bros. isn't aimed at fans of Tekken or Soul Calibur. It's not a traditional fighter. It's aimed at people who want a fighting experience entirely different from the traditional fighter. It's designed to be the opposite type of fighter.
You can't play a game expecting it to be something it's not and have an accurate impression of it. While these types of games may not be your style (thereby giving you a legitimate reason not to like them - which is entirely okay!), you can't play them and expect what they aren't, and be able to say they're good. It won't happen.