While yes it's another tradition, I think there's a reason why God spoke to Moses via the burning bush. Also, before the time of Christ only one person, the high priest, could enter the inner sanctum of the Jewish temple where their God was said to reside... and even then He did it once a year, and wore a rope tied about him in case he was struck dead the other priests without entering the sanctum could pull his corpse out. If we look to our tradition, with the exception of the priest, all those who laid eyes upon Nerthus in her holy grove were slained. These instances could demonstrate that for the mortal mind, the unprepared mind simply can't handle the divine.
I also think that as humans... we don't always have minds open enough to truly see Them. Because of this the experiential information we receive, or the gnosis we gain, is then essentially the best our mind can process that particular information. One person's red-bearded God, could be another's blonde-bearded God, and the reason may not be literally a difference in visual color, but rather what that person unconsciously associates with red, or blonde hair. Or that their preconceived notions shape the reality before they even have the experience, or gain the gnosis.
So then what are we to do about unverified personal gnosis? I believe that portions of our lore no doubt entered into the communal consciousness through some sort of acceptable system that enabled stories of our Gods to be passed to the community most likely through those in special roles like priests, seers, and other shamanic type persons. Today... I think UPG should become verified communal gnosis, when several people independent of one another come to the same knowledge. This has happened on several occassions. I think once it has that this should become part of the knowledge shared with all... but the truth of the matter is to many still treat such things skeptically. Even if UPG isn't shared with others, it still has a valid place. But the impact and importance may reside solely with the individual that came to that knowledge in the first place. It may only have something to 'say' to that individual, and no other.
All these things remind me of a quote from Joseph Campbell: "The mystic and the lunatic both enter the same dark waters; the lunatic drowns, but the mystic swims with delight."