Maybe it is too late in development for a feature like this to be added, but just maybe it would take minimal work and add a little bit more polish to the game experience. So, with Tempest when you build sea units they spawn on the coast by your city. And you have an anchor icon on the coastal tile that you can move to different tiles to choose where your sea units spawn. This got me thinking about land units and how any new unit is automatically placed in the city garrison. What if you could choose to have a new land unit automatically deploy (create a new army) whenever one is built? 

This would be useful when your city garrison is full. As it is now, if you build a unit when the garrison is full, production of the unit halts. You get a warning popup, and you have to make room in the garrison by selling a unit or creating a new army. And the unit completion is delayed a turn. So you have to manage your city queues and garrisons, and it can get tedious. And if your city can produce more than one unit in one turn, you have to make even more space in the garrison, each turn, to make room for new units.

This could be put into the game as an automatic feature: if your city garrison is full, new units will always be deployed in an army on the city center. Or, it could be put in as an option you can toggle on the city view: turn it on, and your units will spawn in an army when built; turn it off, and your units will spawn in the garrison when built. There could even be an icon (analogous to the anchor icon for sea units, but I'm not sure what symbol would make sense) that you could use to choose which city tile new units spawn on. (Maybe that last bit would only be useful in a few situations, and not worth the developers' time. But if you have a long stick-shaped mega-city, it would be nice to be able to choose which end of the city new units spawn at.)

What does everyone think of this idea?

It has been proposed several times. It's an obivous feature.

It's too late for EL now.