This is how I build consensus or vet out ideas with a team. I make a statement for a solution based on the information I have, and ask for a better solution from the team, for them to poke holes in it or simply ask "please tell me why this wont work".

Invariably, you get a lot of good thought.

The reason I have found over the years is that great designs are iterative and by giving out a starting point - even if it is wildly wrong, the team can use that to build upon.

If you simply say "give me a design" you get a lot of hesitancy, especially when in a group environment like a whiteboarding with the team.

If you say "here is an idea, whats wrong with it" you get a lot more engagement from the team because the people involved don't have anything at risk, instead each individual only stands to gain should they be able to improve the design.

If there is a headstrong tech in the group who is divergent in opinion, this approach can provide him with an opportunity to say exactly why his opinion differs and an alternate plan inclusive of his comment can be drawn in parallel and then either direction can be taken. with the other plan as a backup.