Where does the perception that risk is increased on wet runways come from; the published landing distances show adequate margin.
A hidden risk of aquaplanning
Slippery when wet due to rubber deposits,
Dust gathered during dry days turn into a slippery cladding when rain comes along
Even disregarding those possibilities, if a runway is of fixed length and dry numbers give you a small margin, the wet numbers will give you even less margin. It's relevant when we speak of Skiathos.
If, say, 50 m margin is adequate is a subjective.