I believe agile methodologies are a major cause of developer burnout. This "always on" mindset takes it's toll after a while, the constant pressure to implement, bugfix and deploy, resolve production issues and start all over again ad infinitum. While there is no doubt agile is better for the customer, sometimes I yearn for the waterfall model where you have long uninterrupted periods of development where the pressure is off.
I feel the same way about Agile-as-practiced in most places. It has its use case, but making it the standard and sole process of development can turn things into an endless grind.
For the discovery and design process, I appreciate things like Basecamp's Shape Up method:
We use Shape Up philosophy at DEV and it's been really solid.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.