@cmowla:
1. Fell is a less common word for chop or cut, especially used in relation to trees (check the verb definition of it
here). I thought it sounded more fitting to the game than chop or cut because fell seems like an older word (remember all ye Olde English from the campaigns?). I'm pretty sure the woodcutter's description when you click on him even says that he "fells" trees.
2. Well plant only isn't really useful. Try to imagine a situation where you wouldn't want a woodcutter to chop trees? Fell only is useful because you don't want the woodcutter planting if you are clearing an area. Having two woodcutters next to each other, one on plant only and one on cut only won't be any more efficient than having them doing both.
@pawel: You're right, it's already possible to achieve this targeted aiming by pressing halt (H on keyboard) then immediately right clicking an enemy unit, who will then get shot from every archer in your group

Could people please test if this is abusable/exploitable in a multiplayer context? (does it make knight dancing useless?) If it isn't then I guess we can allow you to give your bowmen specific targets.
Another interesting point is that once the bowmen have killed that one unit you told them to shoot, they will go back to shooting random targets. I could make them pick targets only from the group you told them to shoot (and if it's out of range, pick random targets). But then knight dancing would be completely pointless because it would be possible to control which group your archers are shooting.
I guess we need to completely rethink the purpose of giving archers attack orders, like sado's ideas.