You're entirely missing the engagement ranges, the veterancy bonuses, squad size and timing.
Pgrens come far later and will be forced to fight vetted Penals who get "To the Last Man" dealy which makes them stronger as the squad sizes go down. 6 guys at medium to max range will beat up Pgrens who are an assault like unit that performs better at med to low range.
As simple price adjustment wouldn't help. Keeping the price and adding 5th man would be a step in the right direction as indirect fire makes a 4 man squad so vulnerable.
It's highly likely you'll face 3-4 penals and 2 guardsman, and a flamer which puts Pgren at a straight up disadvantage. They'll also lose to Shocks, another popular pick. They have no real advantages which is why they aren't used that much.
I think the best first step for them in order to get them on the field is by setting their price to 300 manpower.
You are right of the fact that it has no real advantages. The likelihood that anyone would use it. For its current price, it has to have more. It is lackluster currently. Nobody picks it because it is so! Giving it armour like what Shocks have is a good step instead of 5 man I believe. To also suit Wehrmacht overall being 4 man and all. Pzgrens should have armour.
I would understand if they were versatile but they are not. They are only 4 man. They do not deserve now to be 340 for the way they are currently. It should have better survivability for that price or something more!!!
It would definitely suit for them to have 5 man for their current price and performance or amour. 4 man is simply not worth the price currently as they drop like flies. Lacks utterly in utility also. Price is simply unjust.
If I had to compare to a Sturmpio. I would definitely take it with every chance since it has much more utility and better capabilities. Cheaper also that comes with a lot more pros than cons. Panzergrenadiers are just not worth it. They need to made cheaper or give them armour like what the Shocks have. Survivability needs to be increased for that price.
340 manpower, for what exactly, costing you more manpower without any real effectiveness?
Even to compare it to Obers. I would even pick Obers any time since they perform better and have more utility for that price.
I did a test:
Pzgrens vs Obers (with MG34 upgrade)
Obers won surprisingly medium range which is supposed to be Pzgrens specialty but that its utter nonsense. Long range Pzgrens lost miserably.
Close range, Pzgrens won usually standing with 1 - 2 models left.
Pzgrens should not be anywhere near the price of 340 manpower for the way they currently are. They are simply lackluster for that price. They need better survivability like armour, what shocks have. It is not a good a unit or even a supportive one. That is why grens are always chosen.
The reason why I would want to pick Pzgrens, is if stands out in one role, which it does not. It fails miserably to suit its current role. It is lacking, the only real purpose Pzgrens have only is AT. No one wants that because Pak is a better cost effective choice that is even more viable in most case scenarios.
Devs needs to evaluate the units according to how often they are purchased and performance. Pzgrens definitely stand at the bottom of the list as the least purchased unit for its overall effectiveness!