Oh that is completely true, in ynnari the +1 ws suddenly becomes usefull, I had not thought about that.
Also remember you are not that safe when trying to run around orks. They can move 5, advance a d6 and charge 2d6 with a reroll. The 18" bubble is you minimum distance. So that means nearly a healthy chance to get charged. In total around 40% chance to charge. (This is assumed you will not charge if you roll less than a 4 on your advance so you have at laest 65% to make the charge so you will not eat overwatch for no reason). And then their 4 attacks (fortunately no pistol shots since they advanced) will make short work of our hellions.
One more question:
Can you mix and match rolling and picking drugs?
Say I pick +1 str for my wyches, +1 attack for my hellions and +1 t for my reavers, Now I have one more unit of wyches, but I do not like the ld move and ws bonus can I now roll for my last unit of wyches instead of picking hoping to get a double?