Well my only comment is that you appear to be overly sensitive of others opinions which when you boil it down most such opinions usually are just subjective in nature. As you seem to be well aware of your own capabilities and skills and the what you can accomplish with AVR chips, you really shouldn't require any kind of validation from users of other platforms or microcontroller chips. A real engineer just uses the devices as tools to accomplish tasks and really has no need to become a 'fanboy' of any specific platform. Engineering is not a sport, it's a process of converting ideas into reality.
Good luck with your nephew, sounds like he will have a great benefit from your mentoring.
Lefty