So that you won't just murder absolutely everything and have no fun because everything dies immediately? This isn't even a question.

I don't want to "see the power of my character", I want to have fun playing the video game. If I really want to feel powerful I can solo bosses using the undersized party option, or go to The Black Shroud and toss spears at random bugs.

And if you're doing MSQ, it especially wouldn't make sense for you to have an "overleveled" character. It'd break the story.