In my very limited experience with the new LM book (been playing with my daemons too much), I too still find the skink cloud build as one of the strongest. An equivalent points in other units such as saurus, skrox, krox or CoC are better served with more skinks IMO.
That said, I'm having difficulty cracking units with good saves, especially stuff like monstrous cavalry and tough-as-nails characters like WoC discolords and DPs. Heck, even large units of white lions are rather impervious to our shooting. A combination of good saves plus mobility, high toughness or many wounds always gives me a headache.
I've loaded up on scar vet cowboys with GW to go armour busting, but they can only be in so many places at once, and running them solo also puts them at risk to warmachines and spells. Also, with just 2 wounds each, all I need is 1-2 unlucky rolls and they can die, they don't have the wounds to buffer against bad luck.
I've also tried metal, which in theory seems fantastic in a skink cloud list, helping to mitigate some of the army's weakness. But in practice, everyone would just be looking out for and stopping searing doom and maybe hounds if a character is involved, and ignoring the other spells. And I don't exactly fancy 6-dicing searing doom with something as expensive and as important as a slaan...
Short of diverting such units all day (which doesn't solve the problem against flyers), what other tricks can we use? WoC armies prove to be especially difficult to handle in particular, multitudes of high AS units that are rather immune to skink shooting, characters that are probably even more difficult to kill than our own cowboys, and I have nothing to stop a DP from chasing down my slaan before eating up whatever else thats left.