I think the decision really comes down to balancing two competing interests - planting seeds with JWs by means of a powerful, factual DA letter vs the freedom to speak with JW family by not DAing.
If you don't have JW relatives and/or friends whom you wish to stay in contact with, then I think DAing does more good than harm. I no longer buy the whole "playing by their rules" argument. To me, such an argument smacks of useless petty pride. It really does nothing to help those inside think seriously about the organization. It's nothing but a selfish assertion of personal ego/power.
On the other hand a good DA letter - emailed to all the publishers in your congregation before giving it to the elders - does a lot to help those still mentally trapped inside.