User blog comment:RoznosicielCiast/Least popular champions/@comment-5015210-20130125115917

That is because they do not... No, wait... That is because there are other champions that can fullfill a certain role more effectively. Even tho I agree that Karma is a powerfull champion, she doesn't fit the role of a support as much as other champions do; Nunu, Alistar, Blitzcrank, Sona, etc. She doesn't really have a way to increase her carries DPS nor any harder CC. It's like playing support Zyra. It is the same thing with other mentioned champions. Poppy doesn't fit the role of a jungler, tank, assassin. Tryndamere has a chance against ranged solo topers but most offtanks will shut him down early. Heimerdinger is a mage but not an AP carry. He needs to be able to deal constant damage but just turrets are not enough nor he can burst a squishy in a QWER combo. Trundle is awesome, but not fun, just like Urgot. I can guess Xerath and Viktor are underplayed because of the high-risk low-reward playstyle. Sion and Zilean are like Trundle, not exciting to play but still very powerfull.