I still say it works well with Takeko, and also with Nori. Giving them 20 defense instead of 15. It's best used when stacked with other defenses, instead of just the 5 reduced damage alone.

yep .. its pretty much balanced combination of defense and healing !!

the warbanner of healing totally out rules the warbanner of defense..
after all, it happens often that characters take little damages, but then do not take damage for awhile.. the warbanner of healing slowly but surely heals these damages up.. and the warbanner of healing doesnt seem overpowered at all - but the warbanner of defense on the other hand does much less and is only rarely of more use than the healing banner....

the changes i'd propose would be the following: first of all, the warbanner of defense should have the 2 turn duration.. secondly , the reduction it grants should be unpiercable...

this way it could really grant quite some reduction, but your enemy can work around it with a few tricks nad whatever, balancing and forcing a certain level of skill of the enemy

another rework i'd propose would be the following:
duration of the effect would still be one turn, but the dr would be unpiercable.. additionally, if an enemy attacks an enemy which is affected by the defensive banner, all non-affliction damages done by that enemy will be decreased by 5 for 1 turn...

this would make it less abusable than the stacking version, but would overall strengthen the defensive abilities of the warbanner, as it also is able to weaken the enemy.. on th eother hand, the enemy does not have to use another non-affliction offensive skill after being affected by the banner... (also note that is think, that the banner should only affect enemies which use some kind of damaging skill on the enemy, and that the effect should not stack[to prevent extreme weakening of AoE characters])

the third thing i'd propose as a method to change it would be:
the warbanner of defense grants 10 points of unpiercable dr for 1 turn if a character does NOT use a skill...
this way, it would grant a very high protection which especially helps against disruptive enemy teams which rend you unable to move, it works perfectly against stuns and whatever...

this is one of my favourite ideas, as it is a different kind of a warbanner, but the more active your team is, the less defense it grants.. but you could get a great advantage by doing noting - which would also grant you a possible advantage in terms of energy...
if this version would be too weak, it could also trigger if a tactical skill is used
the next change i would propose would be:

WoD works perfectly just fine, if you do something to it will disrupt the whole game balance.