I don't know if this has been discussed before (how could it not have been?) but I did a search and couldn't find anything. Anyway, I think the one ability that really makes rangers stand out from other melee classes has always been the tracking ability/survival skill, which are completely absent from DDO.

And it's not like it would be useless in DDO - being able to track certain monsters/humanoids on the minimap would be a huge benefit to any party, and make rangers a much more valuable class, IMO.