Like, legit, in the next Smash, I'd tie Chrom and Robin together in a duo and declone Chrom.
One, because they complement each other with long-range and close-range capabilities. Like, imagine Robin setting up an arcfire, switching over to Chrom, who then does a Soaring Slash. That **** would be rad as hell. Or being knocked off stage with Chrom, switching over to Robin, and then Elwinding back
Two, because this references the FEA Pair-up mechanic with dual-strikes and defends where they attack consecutively and cover each others' weaknesses. During their final smashes, they could even call out their partner to initiate the barrage of attacks.
Three, because
LORE. Robin's entire shtick is the power of bonds between people so it'd make so much sense he'd fight together with a dear friend. Also I know at least one of you here is a weirdo Robin x Chrom shipper so now you can live out your wildest fantasies.
Dark Pit's not unpopular as a Kid Icarus character, just as a Smash character because being a literal clone and all.
And also KI:U is an actually good game so that's two in his favor.
KI:U is legit great. In fact, my BIGGEST gripe is that my hand cramped hard playing that on the OG 3DS. Luckily that's on its way out so if we ever get Uprising 2, it's gonna be on something that isn't shaped like a brick.