Lol, I was being hyperbolic regarding 19 getting killed. I think you get my meaning.
Orcs are not in my local meta (only played against them once in 7th), perhaps they have some shinanagins that I am unaware of.
I still think for the point cost, Wracks more than hold their own.
Some smart positioning in waves should be able to move-block and tie up their stuff for multiple turns. And again, if they dont wipe the Wrack squad it will be back to full health next turn (assuming you survive moral).
But YMMV. I dont really want everyone jumping to Dark Eldar and filling tables with waves of Wracks (maybe that will be my thing). If it doesn't appeal to you, then you do what makes you happy.
Its a big galaxy, and we are all here to have some fun raiding the lesser races