I did a podcast segment for the Skepticule podcast (my regular counter-apologetics segment called Pearced Off) on the self-authenticating inner witness of the Holy Spirit. Something that William Lane Craig often uses to argue for God from a personal point of view that has the handy characteristic of trumping all evidence. See my previous post on this or the podcast to understand further.
Paul Thompson, one of the hosts, brought up the good point that followed on from mine. My basic point is that revelations from God, the feeling of the inner witness, however these might materialise, never add any propositional content. That is to say that these visions, revelations, experiences, add no knowledge, have no content, that they bring to the experiencer. All they do is validate the experiencers’ already held beliefs. A Catholic will experience Mary, or a Catholic understanding of God. They will not experience an Amazonian god.
To take this further, these revelations never come to disagreement with already held moral or doctrinal beliefs. For example, if a Christian hated gays, then any experience of God, any revelation, would almost certainly ratify this, rather than being a revelation of the notion that this intolerant position was outright wrong. Basically, God tells you things that you already believe and accentuates them. 
If you want evidence of this, just google “God told me to”.
This, of course, makes it all look even more suspicious than such revelations already were.
However, there is one comeback to this. People do reform after experiencing God. Whether it be giving up drink and drugs, or an overly promiscuous lifestyle, there are those born again who reform.
There is, though, a counter-point to this. These are positions and behaviours that people often hold that they know, at the time of holding them, are not morally perfect. There is an implicit understanding that these behaviours are less than the paragon of virtue. Thus there is no moral shift in the revelation, merely a self-reflective acceptance and a change in behaviour to align better with such moral beliefs.
It appears, then, that revelations never flatly deny existent moral beliefs strongly held by the experiencer.
On balance, this makes them even less probable as true and real revelations.
