So, how should this information change your writing strategy?
You can't rely on good organization alone to make up for poor critical thinking, or vice versa. So don't dwell on crafting the perfect, wittiest transition sentences. Rather, think out your essay by first outlining to brainstorm quickly, and come up with a sound flow of reasoning that naturally lends itself to being organized. Then, as you begin to write, consciously strive to guide your reader through your reasoning.
GRE essay graders want to read essays that are easy to follow (i.e. well-organized and well-reasoned), demonstrate strong critical thinking and writing skills, and basically show that you think out issues well. If you can give them that, they'll give you a well-deserved score of 6.