Shiren is improved, though not by much. The better visual flair and actual story make the game more interesting. The less sadistic difficulty also makes it easier for newcomers to get into, though the lack of a higher difficulty may make it too easy for the longtime fans.
Shiren does a great job of straddling the divide between accessibility and challenge, presenting a roguelike experience that may well appeal to any RPG fan. Or at least, any RPG fan willing to give it a chance.