We're not used to theophanies involving mountain tops, clouds, transfigurations, mystical appearances, voices, & the like today. It's too flat earth societyish to say, 'Bring em on!' Too politically & theologically incorrect. Maybe we'd be better off if we had more theophanies, maybe not! What do you think?
Most of those who've told me over the years, as a priest, that they've had such a theophany - to stick to that word, even if it wasn't theirs - have been seriously mad! It doesn't necessarily take clinical training to make such a judgment. Sometimes it's just a matter of common sense, quite apart from theological sense. Without in any sense wanting to limit God & how God may or may not appear, it seems reasonable to ask, 'Is that the way God works these days?' The next question, 'Did God ever work that way?' might open up a can of worms, but surely it's valid to ask if how people saw God acting was an interpretation placed upon whatever was actually happening acccording to their beliefs, values, education & understanding at that stage of history. A lot of thinking - & believing(!) people think that kind of thought, ask that kind of question today. Which doesn't at all invalidate what our forbears thought happened, or their response to that.
Often what keeps us sane & balanced is checking out our theophanies or spiritual experiences of any kind with mature, stable, discerning fellow Christians, including, hopefully, one's pastor. There is also much merit in the old anamchara system of soul- friending. Checking it out in one healthy way or another can help us avoid deep spiritual pitfalls. One thing that often marks out goats from sheep is separating oneself from a congregation, or even going off to start up our own because the others have all got it wrong. Taking ourself out of an 'auditing' process, both godly & human, leaves us wide open to getting mountain-top experiences wrong. Which just helps to bring all such experiences into disrepute. That doesn't deserve to happen!
There's no evidence at all that Jesus, Peter, James or John were mad, nor, by association, Moses & Elijah. (Where were all the other spiritual greats, by the way? What an opportunity for a pantheon of them to appear.) But as we may expect, it's Peter, bless his cotton socks, who 'rushes into print' when silence may have been a more appropriate response. It's Peter who wants to set the experience in boughs, if not in concrete, because he 'doesn't know what he's talking about'! Better to take steps to find out before talking, printing, building, etc., etc.!
In the end, the test of any mountain top experience is what happens at ground level. Although that isn't part of today's set text, it's an inseparable follow-up. Whatever summit type experiences we have personally or in the Body of Christ, what we do with it at ground level will sort the goats out from the sheep every time in Jesus' eyes.