Some adjectives like important, necessary, essential describes as well a subjective attitude towards the world. All expressions of this kind requires the congiuntivo, in Italian as well as in English.
It is essential that he come immediately.
It is necessary that everone be calm.
We don't say that the use of the subjunctive is realized as systematically as in Italian, we just want to stress upon the fact that the Italian subjunctive isn't a system completely unknown in English. It is clear that grammatical structures which can't be realised systematically due to the lack of the morphological material are going to collapse in the long run, something that already happened in German with the Konjunktiv, but one could not say either that the Italian congiuntivo is something completely unknown in English.