I use hotel shampoo and shower gel so CE I started CWSing with hang luggage only.
However I do grab as many small shower gels as I can to survive the USA who seem incapable of using the stuff.
Now if the amenity kit had some gel and shampoo that would be a good kit! Other genuine improvments would be a 4 litre bottle of water on arrival. Would cost Ba about 50p and mean no need to hunt out a shop at 10pm or pay £6 a litre in the mini bar.