Line formation:
Form units into a line wider than deep, where each one is positioned according to its specialty.
Box formation:
A box, with weaker units in the center, offering them maximum protection.
Staggered formation:
Form units in a staggered line, so they are far appart from each other, mitigating siege damage.
Flank formation:
Form units into two subgroups, which then try to surround the enemy when attacking.
No formation:
1_ Disable formations entirely, letting units move as messy and freely as possible.
2_ Ideally, this option should be toggleable via heads-up display and through its own hotkey.
3_ It would be nice to have this option in Age of Empires II: Definitive Edition as well!
2 Likes
2 formations that should be in game should be phalanx style line formation and roman manipular style stagger formation.
Only two, though? 
If you want to have only historical formations, there were several, which I found to be very cool, actually. I’m also OK with devs deviating from the “traditional” formations found since Age of Empires 2 
Wanted to bring up a little detail I ommited when trying to replicate formations from Age of Empires 2 via Scenario Editor: the former wouldn’t let me place units closer together (this does not happen in the original game with UPatch HD installed), which led to rather weird ‘big’ looking formations.
Back to the point, the two formations I would use the most, if implemented, are box and line. These would add a lot of value to all units, specially weaker ones, such as archers, priests, siege and villagers, as they would have a decent cover for once. Without basic formations, all weak units are mostly unviable and a waste of resources.
