The concerns are that firstly, theologically, every Christian is referred to in the New Testament as a 'saint'. The Roman Catholic position on Sainthood, Glenn Davies points out, doesn't come from the Bible.
Secondly, there are pertinent questions to be asked about the miraculous healing's attributed to Mary MacKillop for which it appears from the evidence, the answers are a little hard to come by.
http://www.theaustralian.com.au/news/nation/mary-mackillops-miracles-under-question/story-e6frg6nf-1225813303561
Bishop Glenn Davies states that in no way does he wish to belittle the achievements of Mary MacKillop in her ministry: "founding of a religious order and her work among the poor with the establishment of an orphanage, a women's refuge and a home for older women," but he points out these endeavours in themselves do not pertain to being a 'saint' as described in the Bible.
M V Tronson has taken careful notice of the Mary MacKillop Roman Catholic Canonisation process, for as a Baptist and a student of history, he acknowledges the Roman Catholic religion has ministered down through the ages to ordinary people who on the most part have been illiterate, where colourful pageantry and ideas of sainthood have helped bind communities together.
The Reformation in a real sense pulled back from all this to find an original Gospel centering on preaching Christ's death and resurrection (evangelism). The idea of the 'miraculous' in Protestant circles didn't come back into vogue until the quite recent Pentecostal movement, where one can observe miracles 'by the dozen' at every worship service.
The Pentecostals have likewise developed their own modern kind of pageantry involving a very physical service in which whole families can be active – there is dancing and modern rock music, and an emphasis on physical and emotional healing such as being slain in the Spirit (where some people fall backwards and are caught by designated congregation members).
Like the more traditional practices of many religions in various communities, this helps to involve the individual in the spiritual aspects of the various belief systems and contributes to drawing in the people.
Roman Catholic Canonisation, likewise, appears to have many facets, and evidence of healing's and demonstrations of founding benevolent institutions play a part in the Roman Church deciding which protagonists gain which status within the process.
Pentecostal pastors, too, display these healing qualities and many of them have developed welfare ministries of great significance. Yet the two theologies, Roman Catholicism and Pentecostalism are very different on canonisation (and many other differences in their respective theologies).
M V Tronson concludes that as a Baptist, although his theology is quite different to Roman Catholicism, the Roman Catholics will no doubt enjoy the process of seeing Mary MacKillop canonised within their theological framework.
He is bemused however that the souvenir industry will no doubt be a large beneficiary of the process; something probably unforeseen and unintended by Mary MacKillop herself.