Is there a way to send a message to all alliance members?
The discussion board doesn’t notify members about an active discussion topic (and I think there should be notifications if there’s an unread post). I want to send messages to everyone (like asking people to vote).
Unfortunately, there is currently no way to send a message directly to all alliance members at once.
As an alliance director myself, I would also find such a feature very useful. We do have our own forum and a Discord channel for internal communication, which works quite well, but an integrated in-game solution would still be a great addition.
Especially for important announcements, votes, or alliance-wide information, it would be very helpful to have either a “message all members” function or at least notifications for unread alliance discussion posts.
I would definitely support such a feature. 
I hate to always refer to the roadmap because there are just so many things that are “known” but have no concrete implementation date. But this is something I’d probably tackle as part of a planned general rework of in-game messaging once it also supports some kind of group messaging. That same “plan” is also outlined in the roadmap item for the removal of alliance forums.