Just want to share an anecdote of a 500 people company that I'm based in. The company surprisingly nailed all the points that are made by the OP. And the positive effect of having such a weekly Friday All Hands is apparent. This initiative has only been implemented a month ago, and before that there was a sense of low morale in the team as they were in the dark as to the direction of the company and perhaps their work lacked recognition. However, after the implementation of the All Hands, the teams got invigorated by well-deserved recognition from the leaders and in front of everyone. And in general everyone became clearer of the company's mission and key focus through presentations and Q&A. If there are musically inclined folks in the company, it definitely helps to lift the spirit of the team singing along with songs they are playing at the end of it. If you are a leader of a company considering having All Hands, rolling it out as described in the article could set your team in the right path.