Kid Icarus Uprising provides a lot of options for Pit and his literal clone, Dark Pit. unfortunately, Dark Pit (and hell, you could include Pit from Uprising, too) ended up a seriously wasted opportunity to be distinctive for several reasons, and what was actually changed were kind of inaccurate... and as someone who played Uprising kinda obsessively then, I noticed the issues right away, and considering Sakurai was the guy in charge of Uprising, you would think he'd at least help his team maintain accuracy, time crunch be damned.
for sake of context, I cleared Uprising's 9.0 difficulty using a painstakingly crafted Flintlock [Sniping] Staff and no Three Sacred Treasures. I've used about every type of weapon and I have my favorites, but i at least know about everything Uprising had to provide.
first off, Dark Pit's signature weapon is his self-named staff, which was instead made into his Final Smash as a derivative to Zelda/Sheik's Light Arrow. while it's true that Dark used the Silver Bow to compare to Pit's Palutena Bow, Smash's verson has him fire arrows from the Darkness Bow... which slightly exaggerated how little the arrows bent (the Pisces Bow was worse, but packed the most powerful charge shot of any Bow). the Silver Bow in Uprising had good range and homing, but its shots were strongest when fired up close, getting weaker the further it traveled, which would have suited him just fine with a little tweaking to how the Special attack worked in Smash.
secondly, while it's fair enough to have Dark use different variants of the weapons Pit was using, it would have done much better for both of them if ALL of Uprising's weapons were a bit further explored for customs. Even if you were to limit it to the same class of weapons (Bow, Arm, and Orbitars) there's several different ones that would either produce drastically different effects or at least be more appropriate for the custom in question... the Upperdash/Electroshock Arm's variants, for instance, which has either an armored attack triggered up close or a boosted rush that kept going even if it hits, could easily have been replaced by the Crusher Arm/End-All Arm and the Compact Arm/Taurus Arm, respectively, for Pit/Dark.
Finally, both Angels already have Super Attacks in Uprising, specifically during Air Battles. while it's justified for Pit to use the Three Sacred Treasures, its special attack was specifically the Bow's... and bear in mind that Dark Pit also used the Bow's Special Attack during his boss battle in Uprising's chapter 6, which lit up an area before bombarding it with a ton of arrows, dealing multiple hits if you were caught in that area. using the Staff's Special Attack to finish it would have looked much more appropriate for Dark.
to say I have a LOT to rant about on the Kid Icarus characters, Dark Pit in particular, would be an understatement. Keep in mind that everything I stated above would primarily relate to him being made into a Semi-Clone. Decloning him would be a very different endeavor since Smash 4, even if you counted the Ore Club item, still had 5 other weapon categories unused from Uprising. Developing Dark Pit's moveset into that of a Weapon Master would be a very entertaining thing to try out, especially if BotW Link fails to become one.