An effective defense I have designed for creep  CTF involes at least these units:15 thrall 8 archers 2 dorfs 1 jman and puss ghols (optional). Increase the thrall and archer numbers as you feel nesecary. Put the thrall in a circle around the flag with the archers dorfs and Jmen in the middle. This stops any ghols from sneaking around thrall to get your atrillery instead they have to go through.  If you traded for them leave your puss ghols on the outside of the ring of thrall. When and if the enemy charges your artillery shouldn't have to worry about a ghol flank  due to the fact ghols can not get to them. Bring your dorfs up to the point where the attack is the heaviest and let them do their job decimating the enemies forces with a rain of fire. At this point if you got puss ghols they should be pussing the main point of attack also. This not only damages the enemy but freezes them and lets your dorfs and  archers wreak more destruction on the infantry. At this point if I have lured the enemy into a premature attack I like to bring back my warriors and crush them between my thrall on the flag and my warriors. However this defense is still effective no matter what your overall strat is. For extra punch with the ghols give them satchels charges, lay them in the enemies infantry and let the dorfs do the rest. The jman is too be used to heal any damage the dorfs might take from enemy archers. 

																																								
To counter the defense: The first thing that comes to mind is archers archers archers. Obviously if you can win the archer battle then you can pick off the thrall one by one with your own archers and if you chose to dorfs. Also if you can take out the dorfs you have severly limited the defense's effectivness and can probably win with a superior infantry charge. Of course you will have to be worrying about the possible return of units to bolster the defense. The main strength of this defense is it takes time to dismantle. A direct charge will have a very difficult time beating it. Maybe even impossible. This buys you time to react to what your opponent is doing as you feel is nesecary.