Yeah I know, by "only one move that's unique from Roy" I didn't mean that the Up B was the only difference that Chrom had, just that he only had one attack that was completely different from Roy's, since his FTilt and Jab are still functionally the same moves despite the different animations (And the consistent blade damage is sort of a given considering Lucina).
I figured that giving an Echo a totally new move is a fair bit more work than altering animations for the same attack or changing damage values along a blade, so that's why I don't see Shadow having more than one completely unique move from Sonic ala Teleport or Chaos Spear. But hey, I didn't think Echoes would have ANY completely unique moves until Chrom came along, so who knows? I'd be glad to be wrong.
Speaking of alternate animations, it's kind of a shame that Sonic doesn't have any moves that could reasonably have their animations altered to be a karate chop (The closest thing would be his jab, but I don't think it would work...). The karate chop sorta feels like a staple Shadow move y'know? It would be hilarious if his down throw could have been him karate chopping his opponent on the floor in the same way he killed Eggman in some of the ShtH endings. Ah well.