It has been asked why, if torture is objectively immoral, doesn't the Catechism state this unequivocally?
My answer is that the Catechism is to be read, not by lawyers, but by Christians seeking to be holy as the Father is holy. The paragraph at issue lists and condemns a series of acts against bodily integrity. The Catechism is not a manual of moral theology; rules of statutory construction do not apply.
To understand the Catechism, cherchez la téléologie:
This catechism aims at presenting an organic synthesis of the essential and fundamental contents of Catholic doctrine, as regards both faith and morals, in the light of the Second Vatican Council and the whole of the Church's Tradition. Its principal sources are the Sacred Scriptures, the Fathers of the Church, the liturgy, and the Church's Magisterium. [CCC 11, but see the whole of 11 and 12 for a fuller picture]
Note the sources; the Catechism can't be read apart from Scripture and the Magisterium -- and the Magisterium can't be read apart from Scripture, or the Magisterium's own understanding of itself.
So not only is it wrong to read the Catechism without reference to, for example, Gaudium et Spes, it's also wrong to argue that papal bulls of excommunication constitute irreformable doctrine against which the texts of an ecumenical council are to be judged and rejected if found wanting.
Still, there is a case to be answered on the specifics of the Catechism's treatment of torture. The imperfect parallels really do exist:
Kidnapping and hostage taking
...are morally wrong
...is gravely against justice and charity
...is contrary to respect for the person and for human dignity
amputations, mutilations, and sterilizations
...are against the moral law
I don't think the relatively cumbersome condemnation of torture is there simply to vary the rhythm of the paragraph. I think it is there because it represents an honest to goodness development in the teaching of the Church, a development further explored in the subsequent paragraph. To have the sentence read "Torture ... is objectively evil" is to invite just the sort of complaints that have been made about the Church changing her teachings. By explaining the development, the Catechism undercuts the complaints: No, this isn't a novelty of the tyranny of nice, it's a fuller recognition of what has been revealed by Christ.