Yeah, J-Stars just seemed really half baked to me.
Ultimate Starts blew my mind back when I first played it in when the fan translation was first put out back when I was either a Freshman or Sophomore in high school, can't remember, but how many characters there were, and the amount of detail and thought that went in to building a great koma deck really impressed me for a licensed handheld game at the time. There were so many other little touches that really made it feel like it's own unique franchise of an arena fighter. It's been 10 years since JUS was released, so here's hoping that they dust it off for the 50th anniversary in 2018. If not, they probably never will. (Although then again, the One Piece DS and 3DS fighting games play like a simplified JUS)