I think they should stay the way they are and just a slight cost decrease. They are easily the best flankers on the Ost side. They just lack durability and cost a kings ransom and need alot of expensive reinforcement.
They aren't supposed to be line infantry that soak it up- they are specialized for flanking runs. If the game has people spamming PzG instead of grenadiers, then the meta is broken.
PzG should be 2 squads max IMO. There should be twice as many grens as PzG.