On a side note, i used to wear a Strings also and switched to a Krealm's. It was way worth it (30k+ shards, still no witching hour) i think you should try it to see if you like.
some quick math -> you have 35% cold dmg without the bow (51% with it). that means that the 16% is about an 11.8% increase in cold dmg. If you sacrifice more than 11.8% dmg to get your BP, its worth to use the Windforce, if not, use the Etrayu.
#1 the damage on the weapon (2516 vs 2422)
#2 what BP (breakpoint) are you at? do you need the attack speed?
ill try to find the link to the topic with M6 BPs.
**Found it: http://i.imgur.com/GNkLjIu.png credit to: http://us.battle.net/d3/en/forum/topic/7979318741?page=1#4