Don't change Stampede immunity to immobilize instead make it 9-12secs like soulblader immunity because its helps a lot to survive in immo class like soulblader, WWalker, Wizard especially in Battelfield and PVP maps.
Its better to knockbacked than get immobilized at least u have chance to run in battlefield and PVP maps NOT in duel -.-"
Just my thoughts regarding on my class since i'm active in PVP and battlefields.
-Demonsoldier