Right now, as a Sejuani main when im Jg. I feel like her ulti is still strong as f.
It stuns one target, and that can still be huge.
Deals a lot of dmg.
Slows a bunch.
Disrupts other team's structure, throws things into complete chaos while giving her team WAY more power than before since the rest of Sejuani's kit is still quite good. Before she was a stun bot. Now she is a GODDESS.
Before it was ult and allow allies to do work while your kit was relatively weak.
With the exception being mostly in Early S5 when Cinderhulk was OP. Ult and just walk in and then Q a carry, then slow with E as Cinderhulk killed them and W dealt more dmg XD. Before rework, it was more balanced.
In conclusion. Nerfs need to come in NOW.
However, to where it will go is to be debated.
If it nerfs ult, that is fine with me, rest of kit can be overloaded.
However, if rest of kit gets nerfs, what was the point of rework?