UI/UX/Web Designer = Consensus Builder

Most web/UI/UX designers will tell you their job is to solve complex problems in a way that will create a nice user experience.  Because of this, they will often go away during the design phase of a project to solve the problem then bring nearly completed design back to the team. This approach often fares poorly, because a web designer's job is, first and foremost, to build consensus.

Good design is rarely the result of a single person's answer to a problem.  It is almost always the product of a team of people understanding business and customer/user needs when forming a solution.  But having a great team is not enough on its own, it takes someone who can see what the end goal might look like, and find some way to illustrate what they see in their head (their mental model), and express it to the rest of the team.  Its often called "shared vision".

A web designer is usually the best suited to build that first glimpse and share it with the team to get the process going.  Storyboards, wireframes, sketches on napkins, whatever.  Someone needs to provide a glimmer of what it might look like, so everyone else on the team can be assured they are talking about the same thing.

So web designers, stop getting in your own way trying to perfect a solution, just throw an idea on paper and start talking with your team.  I guarantee you will get better results.