I do wish that this destiny benefited bows more than repeaters, but I think any suggestions towards that end would fall on deaf ears, so haven't bothered till now to make any. The suggestion I would make would be to make the proc chance on the abilities based on rate of fire, with higher rates of fire giving lower proc chances, and specials like many shot not counted in such calculation (just base weapon fire rate).
If I were going to do the epic moment for this destiny I would have it be one of two ways. The first choice I would do would be every enemy in range gets struck by an arrow as if you had fired it from you currently equipped bow every second, and have this effect be affected by your ranged combat feats. All proc chances would apply. The second choice would be to base it on your fey favor stacks with the queen sending you a squad of 5 epic pixies (flying archers) per stack of fey favor, lasting for 1 minute per stack of fey favor. Either of those would feel epic to me. The current epic moment doesn't feel right, it sounds cool, but at the very least it is miss-named imo. If its not hitting them with arrows it should be called something other than rain of arrows.