FFXI's Campaign and Besieged had fortifications and NPC soldiers that were influenced by various player driven aspects. Even the campaign-esque system that came with Abyssea (I forgot it's exact name) had those systems, and even allowed you to set up traps to slow down and damage enemy forces before they arrived at the base you were defending.

So these ideas actually do have some merit with FFXIV, as they were a part of another FF title in the past.

All people here are suggesting is that we tie in crafters and gatherers this time around so they can be a part of the cause as well.