The ability to effectively coordinate and communicate between allies is not intended to be provided by the game. That is something that alliances must work it for themselves, using the tools provided. Inefficiencies in coordination between allies is one of the big disadvantages that groups of realms will face when they elect to team up on another realm. Smaller realms benefit from several economic advantages, including higher tax rates and better realm control, and some intangible benefits such as greater flexibility. They pay for it by having some added difficulties, such as a more fragile and less robust communication system.
If you want to have flexible, redundant lines of communications, you have to build that yourself using the various tools at your command, such as guilds and secret societies. Many alliances have been able to use these system to great advantage, effectively eliminating the problem, and turning the system into a great advantage. It takes some effort and some planning, and that is intentional. If you have the forethought and planning, and the necessary buy-in from your allies, then you can reap the rewards of your accomplishments.
You apparently created a system with a single point of failure, where your general was the only one who had the adequate contacts to coordinate? Why isn't your ruler part of that same guild? What about your marshals, and vice marshals? What about anyone else interested in the military aspect of the game? How did you expect anything other than crappy results, when you deployed a completely inadequate system? If you have a system that is so fragile that a single general getting wounded screws you over, then you have no one to blame for the resulting difficulty but yourself.
In regards to sending one message to multiple recipients from the contacts list, I am not completely familiar with the reasoning behind that decision. I believe that it is along the same lines as previously discussed: It is not intended for random nobles to be able to create their own ad hoc lists. The game creates multiple lists for you automatically, including your realm, duchy, region, government, guilds, religions, and secret societies. Options are also included for rulers to create a limited number of additional realm-specific groups. If you want to create other lists, then you will have to create the infrastructure for those lists. I.e. create your guild/society and get your allies to cooperate in spreading it around. If you can't get their cooperation to implement if effectively, then perhaps your goals really aren't all that important to them, it they just aren't competent.
Communicating outside your realm is indeed limiting. It's not supposed to be easy and convenient. That's where things like tournaments, guilds, and societies come into play: inter-realm communication. Many guilds were created specifically for the purpose of facilitating communications across large numbers of nobility from different realms. The nobles who take the time to travel the island, join the guilds, and assemble those contacts can reap great advantage from them. (I know of many nobles who toured an island during peace time specifically to join the guilds and build those contact lists. They became invaluable diplomats and sources of information.) If any noble could create ad hoc lists on the fly, then things like guilds and societies would become pointless.
So once again:
"Reply to List" for realm wide messages: Desirable. I support it, and I believe that Anaris or Vita are working on it as they get the time.
"Reply to List" for a self-selected group of "Some" recipients: Not desired.
Sending a single message to multiple recipients using the Contacts list: Not desired.
