The more senior the designer, the more abstract the problem they should be solving.

A senior designer will be highly generative with ideas and solutions if they feel a deep ownership with the product vision and strategy. 

Conversely, if a senior designer is given a junior-level task (like ‘design a form’) but feels that a form is entirely the wrong way to go about solving the problem, then they’ll probably be deeply unhappy with what they’re doing, and possibly not do that great a job either.