The table you are quoting is literally saying a vet 3 (2) Panther has more frontal armor (286) than the KV-1 (270). The Panther having less rear armor than the KV-1 is logical because of their roles and it is realistic on top of that.
Considering that Panther is Wehr main tank to counter Allies heavy, yet its armor is weak to support this role as a mobile tank counter. It got no vet bonus to supplement this role, no penetration increase, no move accuracy increase, no damage increase. Just weak 90-99 armor on its 2nd half that even cheap SU76 can deal 120 damage from 60 range. SU76 need not flank it, just have a nice angle side opening, i repeat rear armor is not rear armor, but 50% of the tank.
Allies TD all out range it, allies infantry all have super fast snares, Soviet even have heavy engine damage. And best of all, Allies TD on vet get pen bonus that completely ignores panther vet armor. Poor scaling for Wehr, dont you agree?
And when you list out all TD available to each factions, their ranges, their penetration, their damage, their accuracy, their vet bonus. Dont make sense why Allies need so strong rear armor tanks that are still popcap affordable.