There is no such thing as criticism; there is only history. What usually is passed off as criticism, the things you find in architecture magazines, is produced by architects, who frankly are bad historians. As for your concern for what should be the subject of criticism, let me propose that history is not about objects, but instead is about men, about human civilization. What should interest the historian are the cycles of architectural activity and the problem of how a work of architecture fits in its own time. To do otherwise is to impose one’s own way of seeing on architectural history.
What is essential to understanding architecture is the mentality, the mental structure of any given period. The historian’s task is to recreate the cultural context of a work. Take for example a sanctuary dedicated to the cult of the Madonna, built sometimes in the Renaissance. What amazes us is how consistently these buildings have a central plan and an octagonal shape. The form cannot be explained without a knowledge of the religious attitudes of the period and a familiarity with the inheritance from antiquity — a reproposal of the temple form devoted to female divinities. Or take the case of Pope Alexander VII, whose interest in Gothic architecture at the cathedral of Siena [mid-17th century] compared to his patronage of Bernini in Rome can only be explained through a knowledge of the Sienese environment and traditions. The historian must evaluate all the elements that surround a work, all of its margins of involvement; only then can he start to discover the margins of freedom, or creativity, that were possible for either the architect or the sponsor.