19 years ago, I started attending WB seminars when I was at IFPRI. There were great presenters with great papers, and I was really excited to get to go to those. Then I stopped attending entirely because of the ridiculous constant questions, which, as Berk points out, were almost entirely questions that were clearly going to be answered in the next few slides. Constructive criticism was nearly entirely absent.
Since then, I've given 3 or 4 seminars at the Bank myself, and I've always imposed a 15 minute question moratorium, and I believe that that's the only reason I generally got very helpful constructive criticism.
I think there are two separate issues; one is that questions by anyone in the first 15 minutes are generally unhelpful, uninteresting, and not constructive -- for the speaker. A side effect is that it's also really annoying to the seminary participants who actually want to listen to the speaker speak.
I see this as separate from the gender issue, though potentially inter-related. It would be interesting to see if the 15 minute moratorium also leads to more gender balance in the questions. It might be if the moratorium also reduces the preening questions. But, you also noted that if a woman asked the first question then this also reduced the gender disparity, so a chair could make sure that if there are multiple hands up for the first question, she tries to choose a woman.