A curious claim met my eyes recently, in the Ashgate Research Companion to Byzantine Hagiography, vol. 1. On p.148, as part of Symeon A. Paschalidis “The Hagiography of the Eleventh and Twelfth Centuries”, we read the following words (overparagraphed by me):
An important catalyst in the decline of hagiographic production in the eleventh century… was the contesting of the elevation of new saints. During this period the view was widespread that it was no longer possible to become a saint.
The philosophical position of the philosopher John Italos, a pupil of Psellus, who called into question all miracles attributed to Christ, the Theotokos, and the saints, also had some influence in this respect.
Our two most important sources for this dual contestation are two texts…
This sounds rather interesting. The two texts are:
- Nicetas Stethatos, Against those who accuse the saints (Κατὰ ἁγιοκατηγόρων). [UPDATE: Online here]
- John the Deacon and Maistor, against those who call into question the cult of the saints and argue that the saints cannot help the living, especially after their deaths.
These texts are hardly accessible, however. Paschalidis himself has published the Stethatos text in S. Paschalidis, “Nicetas Stethatos’ unedited speech Against those who accuse the saints and the question of sanctity in eleventh century Byzantium” [in Greek], in: E. Kountoura-Galake (ed.), The Heroes of the Orthodox Church. The New Saints, 8th-16th c., [NHRF/IBR, International Symposia 15], Athens 2004, p. 493-518. The relevant portion is 515-8. 
The reference given for the other item is J. Gouillard, “Léthargie des âmes et culte des saints: un plaidoyer inédit de Jean Diacre et Maïstôr”, TM 8 (1981), 173-9. “TM” turns out to be that not entirely well-known journal, “Travaux et mémoires du Centre de recherche d’histoire et civilisation de Byzance”, which I gather has a home page (if no content) here. I am unclear whether this even contains the text; how one might obtain the article is quite unclear also.
I think by this point we are perhaps outside our period. But it is very interesting that these questions are being raised around the time of the great collections of hagiographic material. Perhaps some medievalist could obtain and translate these texts and place them on the web?
UPDATE: A kind correspondent notes that Paschalidis has a scan of the first text online at Academia.edu here. This is not searchable, which means you can’t use Google Translate on it. I have therefore run it through Abbyy Finereader 12 and the output is here: