you know i really dont think sejuani is op in solo Q. i think if perhaps you are organized or on a team she might be. her kit is great, the slows, knock up and % damage are all fantastic. but hitting the ult on the important people isnt always easy, she cant do ANY DAMAGE ever and even if you get fed how will you carry with a support jungler?
plus her dragon control is atrocious and shes not that tanky. it really bothers me whenever i pick seju and do great my team will just flip their lids and lose the game and i cant carry on her like some other junglers.