The UN is a political organization which means they will try their damndest to be "politically correct." This action you want them to take is anything but. The UN, rightfully, stays out of religious matters. That's basically what this is -- a religious matter.
The UN has nothing to gain by posting information which will be derogratory of a worldwide religious faith. Stroking the apostates dicks is not exactly on their agenda. The UN has already provided plenty of information to individuals regarding the Watchtower's NGO status with the UN. This information is easily found all over the net and in the most recent version of Crisis of Conscience. Honestly, what more needs to be done?
Letters of this sort will only make many ex-JWs look like a bunch of fanatical dissidents out for revenge against their former religion. And, if by some miracle this action is taken, the WT will only point to it as a fulfillment of prophecy ala their "persecution complex." I thin more harm than good would come of this action.
But hey, if you think otherwise...good luck.
Bradley