You are right in that Zoroark does have a ton of move set potentials and more than enough things to make him unique. Though I used to be opposed to Zoroark for really silly reasons, when I grew out of it, his move set potentials is something that could be awesome if done correctly (especially Illusion). Had Gen 6 not started development at such an early time, Zoroark would have been a very real contender to get into Smash 4. The only comparison I made was that Zoroark was expected but not wanted by many people. But I would say that Zoroark would be a better choice than Chrom overall.
But getting back on-topic, let's think to Sakurai's four criteria. One of them he mentioned was that a character had to be unique. Now granted, while this doesn't mean that a character needs move set potentials to be unique, it does show that the character shouldn't be generic.
I'm not even sure if Chrom stands out at all. I mean, Lucina plays as important, if not more of an important role than Chrom does when she arrives, FE13 is basically FE All-Stars, and Chrom is a pretty dull character overall. I question if Chrom even meets the criterion of having to be unique. If he doesn't, then he's out. No amount of screaming recentness as a reason to put him in (let alone axe Ike for him) would change that.