I know what you mean, DE just get minced by Guard/GK/SW psychic nonsense so a Farseer is always a good investment for dark eldar armies these days.
I would suggest Fortune for you Farseer. I know its more expensive but if you fortune those Pathfinders, effectively people are going to have to come and assault them to shift them as they wont be doing it with shooting (aside from podding Vulcan marines with flamers obv).
Also, find 5 pts to give one of your Haemos a shatterfield. It can remove any infantry model from the table, so far I have gotten rid of most of a unit of Crushers (lucky, yes but still possible), Grimnar and Moloc. One use only, but how many liquifier shots do you normally get off anyways?