1. It is not currently possible to adjust the shape of the word cloud.
2. The font size of the words is data-driven and indicates a value (for example, frequency.) The font family (for example, Arial) can be selected. The font color can be selected, or if a data item is assigned to the color role, the color is data-driven.
3. As mentioned above, the size and color of the words can be assigned to data roles.
Depending on your Visual Analytics license, you might also have access to Text Analytics, which provides additional metrics and features such as sentiment analysis.