Two things: first, Rikku has lighter colors than the rest of the image, her colors should be darkened to match them; second, this is her battle sprite which should be altered to be a non-battle sprite (in other words, her hands should be hanging loose). I can do those changes if you want. Heck! I might as well make her a full basic sprite if there's need. I can do them for all cameo characters if needed. ;)
I think that was more or less just the graphical style before FF6, since overworld and battle sprites were two separate things prior to that game. I can (and will) easily do it myself if others have an issue with it, though. I definitely don't need/want full sprites complete with animations for any of the card tournament opponents since they just stand where they are and react to winning/losing, etc. I might edit her colours though, since I never paid attention to how bright Rikku was before you made that comment. At the very least, her hair could be changed to a different shade of yellow. Maybe something akin to Jasmine's hair (how convenient that she's the one in the screenshot).