im guessing your playing the drain game which is totally useless since they buffed mana shield, you gotta dps the warrior and pet destroy totems, time your cc's with ur druid and druid help dps and you can take any warrior down even if with shield, don't forget to put a drain on shaman when he is free to heal cause they go oom very fast when healing burst and no time to dispel vipers, well i think this is the onyl way to beat a shaman/war is by nuking war
hope this helped