is flash sejuani worth it

Depends on your skill level and the skill level of your games. Q flash or R flash combo are probably unheard of below gold and rarely used effectively below diamond, but they are also a nearly guaranteed engage tool. So if you don’t take flash you are essentially missing out on the best parts of her kit.

i just played two matches as sej vs trundle ai intermediate and boy is she under powered i like winter wrath the rest stink the armor is neat but useless when you do have to fight--sustain nerf the 3 stats that have to be maxed is worse than ad ap hybrid she is a gas guzzler
whats cool is executioners calling + wrath passive is ok in that it allows you to not be slowed, but it doesnt work with mobility boots [cass-cry]