So I'm kind of new to the game and managed to land in a rather sizable Free Company. So large in fact that branch Free Companies are required in order to accommodate that constant influx of members.

The problem with such Free Companies or even alliances between multiple Free Companies is communication. I mean, each Free Company has its own chat and I imagine that developers would probably not expect multiple free companies to come into an alliance or grow to a point where they require multiple free companies to function, but in such instances we have no tools to effectively communicate with each other.

Linkshells provide some relief, but with a 128 player cap they do very little.

My suggestion is that a line of communication be opened between Free Companies that enter into an alliance with each other be allowed an "Alliance Chat"

This would function as another chat (say /a) that you could choose to use or not.