Epiphanies go in and out of fashion. Joyce used them extensively in "The Dubliners" but in an age where closure is distrusted and deep truths ironised, the tidy epiphany has been sidelined. As pointed out in Epiphanies on film, it doesn't help that they're "overused in television series, where they are usually a cumbersome attempt to add depth". An epiphany that's supposed to make all the pieces of the jigsaw suddenly fall into place can end up looking as contrived as the final scene of an old whodunnit.
Dickens' Scrooge is often mentioned as an example of a character transformed by epiphany. Another example (without a self-realisation component) is the end of the first "Planet of the Apes" film. Gambling the effect of your story on a final epiphany is a bit like gambling on a punchline - if the epiphany of a short piece fails, the whole story does. Epiphanies needn't be near the end of a story though. Instead they can signal a significant change in the plot direction - a new start.
It's partly a show-not-tell issue - the reader rather a character should experience the epiphany. It may be hard to make readers experience the described epiphany, but they might be encouraged to empathize with the epiphaniser, or at least understand the character development. Jordan E. Rosenfeld in "Make a Scene: Crafting a Powerful Story One Scene at a Time" lists five types of epiphanies (removing blinders, realizing a suppressed desire, accepting the limitations of oneself or others, experiencing identity epiphanies, undergoing a rude awakening) and suggests ways to pressurize characters into epiphanising. These processes should interest even epiphany-weary readers - you may be able to satisfy them without spoiling the story for others.
Your own epiphanies
You see a beautiful sunset. You're moved, drowned in thoughts of your mortality. You photograph it. At home you show it to someone. They're not impressed. When you look at the photo again even you're not impressed.
Judging your own writing's never easy, but judging the literary impact of your epiphanies on others is harder still. Psychological epiphanies add further complications. When a divorced woman realises that a suitor is only after her money, the force of the revelation may be overwhelming because of the internal resistance that the revelation had to overcome. To her friends and family the situation might have been obvious from the start - it's not a startling insight to anyone except the woman.
You can avoid writing about epiphanies altogether if you feel your judgement is too clouded by private experiences, or at least avoid using your own epiphanies. Alternatively, you can hedge your bets by offering routes through your stories for epiphany-phobes
- The epiphaniser can express their awareness that the reader might not empathise with the epiphany.
- Someone else in the story can express doubts about the epiphany, either to the epiphaniser or just to the reader (dramatic irony). Maybe the sunset was the result of an up-wind pollution event. Maybe the woman felt so lonely that her friends let the friendship develop. Maybe the epiphaniser gushes several epiphanies a week.