As a person who has had and Echo since the first one was developed I have the following suggestions none of this should impact the content, just the style:
Should be able to change the wake word to anything determined by user.
Should be able to set personalities: Examples: Sassy - Subservient . Jolly - Sad. Joking - serious. Sexy - Prudish etc.
Should be able to choose the voice: male / female and perhaps the accent.