Yes! Come to poppa! Give it to me baby!
Well, that would be my reaction if I saw this added in a patch readme.
It would be even better if you could have some "favourite pick" formations you use often to just go with and then adjust what's needed. But that can probably be done with formations as they are right now, so Noble's idea would be enough methinks.
And both attackers and defenders gets to do this. Very important. Especially if TCP/IP play is added because in AoW only the defender can do it and alot of time is wasted waiting for the attacker to get into formation before he/she advances.