I recently noticed something similar with the thunderblade and frostblade: they both stop enemies from moving. While the thunderblade stuns, the frostblade freezes. However, is there any other major difference between the 2 weapons that isn't obvious such as damage, stun/freeze time, etc ? I still don't have either weapon so I can't test it for myself.
Note that the obvious means like how frostblade works better in hot areas such as Death Mountain.