I'd prefer they stay homing/unlimited range. If not, then I demand that the Trolololol song starts to play every time a panther uses blitzkrieg and runs through your lines at 250mph without risk.
I would rather have the Trollololo song playing, but that's just my opinion MVGame
On a more serious note:
At-nades/buttoning/mines are the only tools at your disposal to counter blitz'd armor, though each one is not 100% guaranteed considering buttoning=smoke',mines=ability to draw your opponent over it with luck on your side, AT-nades= 50% chance of damaging engine, but blitzkrieg is still operational.
So honestly limiting the AT-nade radius is a bad idea imo, and should only be done once Blitzkrieg is nerfed alongside with it.