Decide what the meeting is for.
An all-hands should do things email cannot: let people see leaders, hear honest answers and feel part of one company. Pick two or three messages and cut the rest.
Share the agenda early so people can send questions in advance.
Run it so people stay engaged.
Open with the most important news, not a long welcome. Keep slides few and spoken parts short. Leave real time for questions and answer some hard ones directly.
Use a facilitator so leaders can focus on listening and answering.
Follow up and reuse.
Publish a recording with captions and a short written summary within a day. Cut a highlights clip for those who will not watch an hour.
Answer unanswered questions in writing and share the answers with everyone.