Agree the process of translating words into visuals still lies with the designer. However I've found that if the team spends more time collaborating before this point, design exploration is more thorough.

That said the process is not bulletproof. Sometimes a great idea is identified in the Google Doc brainstorm but it takes a fe tries to translate into visuals. And sometimes the visual fails completely, but I've found this to be a rare scenario.

Ultimately this method cuts down that risk, but doesn't eliminate it.