JP4 is so controversial that nobody can agree about actually anything
Some say it is UP, some OP, some say it is slightly bad, some decent. What the hell.
The jp4 is good because it must be, from a design standpoint.
OKW gets either squishy lights or expensive but armoured mediums+. You simply cannot lump them in with "other TDs are squishy" and ignore faction design. There is no cheap t34 for shock and expendable awe. There is no Sherman HE. there is no cromwell with flanking speed to get up in them guts. Jp4 gives okw a fighting chance against cheap allied armour whilst still holding true to faction flavor and design.
p4 gets almost heavy tank level scatter with vet, while already having rather good scatter for a medium combined with good AOE and great OHK potential. Yes, it has a premium price tag, but it is well worth it.