Maybe try giving her passive auto attacks that deals magic damage and scales with ap. Problem when i play sejuani is that i cannot damage the jungle creeps, enough to clear the jungle fast enough.
3 x Attack Speed/ 6 ArP Reds (5% As with 10 ArP)
9 x Armor Yellows
9 x Scaling MR Blues
3 x 26 Health Quints (73 HP + The 30 From masteries = 1 more dps on her W)
It seems to increase my speed and Increase my early Health to a point where I can gank.
Though she will be slower without MS quints. The key becomes getting that first hit on the target to start slowing them, especially once E hits level 2/3.