I think it's wort a try. Stressed yeast is more genetically different than the original strain. Under low stress yeast reproduces by budding so the child cells have almost identical DNA to the parents. Stress encourages yeast to reproduce sexually causing different DNA in the children. This can cause recessive traits to become active in the child cells making them preform different than the parents.
I just pour the slurry into mason jars and put them in the fridge to save yeast. It's worked fine for me. From testing I have done it seems that yeast washing does not improve the quality of the yeast at all. It only throws away good cells.
Here is a write up:
http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html
I would be happy to test your slurry. If you are interested send me a PM.