Are we talking about a double attack, means 2 (or more) attack markers, say a move order to FUP 1 then attack target 1, then move again (and change the direction) after the assault has finished (instead of collecting all units + switching to the defense at the former attack marker) and attack again (target 2), or say move to destination 2?
I'd call this "multiple main task chain", and it would be a nice tool for gun + run tactics, say for a unit that is supposed to harrass supply lines in the hinterland or tasked with pestering enemy units on the enemy MBL from behind (ie. para units). The player could also arrange for a complete mini campaign in one sector, while taking care of other units manually in more important sectors.
You could also precisely schedule feint attacks that way:
ie. a) move - b) form up - c) attack A - d) withdraw to point X to defend/hide in woods at location X - e) relocate to Y in 2 hrs - f) attack B - g) withdraw to Z after 30 minutes), while your main force attacks from a different location. Thoroughly timed feint attacks were pretty common and used by all nations.
I've always thought that more complex sequencial tasking (which would allow for more detailed/complex planning) would be really nice, especially since I often hit the FFWD button during calm periods. Say the game speed is on FFW, then there is a chance that new orders for an idle unit get delayed, because I have to adjust orders for other units that are getting in deep trouble suddenly (say a massive enemy attack, heavy arty shelling, etc.), even if I pause the game, means the FFW speed causes the waste of 3-5 minutes where then some units just sit there idling, until the game is paused, occasionally. The delay may even be bigger, if I switch to the highest game speed, say 10-15 mins. Such delays may add up to a crucial amount, say in situations where objective points have to be collected over an X amount of time, for instance, means where a total 1 - 3 hrs of delay over the course of the scenario may contribute to a draw/loss.
I can't remember, is there an option in CO2 that pauses the game once one of your units starts to retreat/route, nowadays?
If not, this might be a nice addition.