Epicness is not a bad thing. Detailed worldbuilding, sweeping grandeur, and amazing scenes can create a compelling story. The detailed languages of Tolkien's world make it feel authentic. The sheer size of Erebor, of Cirith Ungol, of Minas Tirith, awe us. The finality of the last march of the Ents, of the death-ride of the Rohirrim, can make our hearts burn within our chests and our fists tighten. Tolkien's work resounds with epicness.
But epicness alone isn't enough. Epicness can be a taster to draw in readers, but it shouldn't be the full meal. Give a reader an epic story, and they'll probably remember it. But after it's been read enough times, the epicness wears thin. Reading about the same amazing scenes and magnificent structures over and over again can get tiring.
But not theme. The best books are those that can be read over and over again, each time picking up some new nugget of meaning and insight, some new thread of hope, some new morsel of mental or spiritual food.
Epicness doesn't do that. But theme does. As does characterisation, which is implicitly linked – I believe – with theme. You can't have a resonant theme without strong characters – at least, not without it feeling forced and contrived. Artificial.
Great stories should have great themes. If a reader is going to take the time to read your story, take the time to give them something meaningful, something worthwhile, out of it.
I'm not against epicness. Give your stories all the epicness you can imagine. Make epicness run home to its momma crying. (Semi-inside joke, if you didn't get it). But give them something that will stay with them forever.
