Final answer:
Desirable features in a widget toolkit are consistency and simplicity because they enhance usability and user experience, whereas excessive complexity and randomization can hinder user interaction.
Step-by-step explanation:
Desirable features in a widget toolkit include consistency and simplicity. Consistency across widgets ensures that once a user learns how to interact with one widget, they can easily understand how to use others, improving the user experience. Simplicity in design is essential as it allows users to accomplish their tasks without unnecessary complexity or confusion. Overly complex and customizable widgets might hinder usability, while randomization and variety could cause inconsistency and user error. Uniqueness and innovation are valuable to set a product apart; however, they should not come at the expense of the core usability principles.