Hello. I was reading the Beginner's Guide and thought I would share this. Incase noone has mentioned it before.

Quote Originally Posted by A Beginner's Guide to Rome: Total War
Remember how you used to set your army up in a nice, pretty formation, then select them all with ctrl+a then hold alt and click to move them, and they kept that nice, pretty formation and facing? Well, not any more. Tragically the ‘move but retain facing’ command is gone and there is no substitute. Moving your army even a few paces forward invites them to slant the line and present a nice vulnerable flank to the enemy. When dragging out a collection of units into a new formation you will only get a single line if you put them in the single line group formation (default shortcut is shift+1), whereas before this was not necessary.
There is a way to keep your custom formation, unit proportions and positions and have them all facing the same way when moving them. If you organise them in the custom formation you want, then select all (this also works with small groups of units), then put them in a group, they will keep their exact formantions. If you try and right drag the group to a new position you will notice that the units keep their formations and unit width.

Note: If you want to change the formation in any way or change any units width you must first remove that particular unit from the group, make the changes then put them back into the group.

I hope this helps and saves some frustration. I know it annoyed me when all the units would try and run to the exact same spot or be streached in 1 long line after all my hard work getting them how I like them .