I rather love sejuani jungle. Although it's true she runs oom so fast jungling without blue, you can pick up things like a philo stone and glacial shroud to help. Those items aren't really even an inconvenience either, because who couldn't use regen/gold, while the shroud is a good tank item(I like it anyway).
She's also not that slow to jungle, especially after level 3. Q into a camp, hit e, then w. Bam, cleared.
Yeah, her slow isn't as much as red buff, but it's enough to keep people within melee/w range if they're just running because they don't have an escape.
Wouldn't mind seeing her buffed at all, but I really don't think she needs a rework.