I feel like some people are missing the point here. It doesn't matter if he signed Stones or not, he never played for Moyes and therefore was not building on Moyes team. Moyes probably wouldn't have even looked at him that season.
We fell off a cliff because he chose Moyes keeper over his own (better) keeper, the "boss" defence was all getting old (Hibbert, Jagielka, Distin), Osman was also getting old and we had zero usable strikers apart from Lukaku as Moyes left him with none and the player he did bring in to fill in broke his leg.
It's not a case of either or anyway, it's just a case of not letting this utter myth of us having a good season was due to Moyes' team. It really was not, it was a totally different team. It needs knocking on the head.