Amazon

Working with very intelligent people, there's a lot to learn.

Some rigid employee-related processes.

Extremely difficult and subjective promotion process that requires politics in some cases.

Compensation-wise, the company may favor new hires over seasoned employees with valuable contributions.

To move to a different team/role, it's not possible to change levels, even if the new team strongly thinks you're worth the next level. The only way is to quit, wait (I believe) over 6 months, and then interview again. A new hire will get the level, but if you're already an employee, it's not possible without the formal and very long promotion process.

This applies to changes from an engineering to a management level. For example, level 5 engineering is not junior, but level 5 management is junior. Making such a move would cap compensation lower than currently.

To listen to employee complaints. It's a large company, and individual complaints may not be heard or acted upon. Simplify the promotion process and give incentives other than status. Right now, the only target it seems to have is to squeeze life out of employees for no real reward.