I think the point was that maybe ST should be fragile enough to have decent chance to be penetrated by medium tanks. Nobody said that P4J should have lower armor etc, because at 8CPs, more often then not, you can afford a ST and just indefinitely bully your opponent without fear or repercussions.
To be frank here all early heavily armored tanks have this problem. Any heavy tanks (even KV-1 with its meh penetration) can bully medium tanks without much of a fear early into the game.
But its not the point. When we take ST suviability into a considiration, its indeed is very sustainable to damage, but lets be fair here AVRE is not different in this regard.
I mean, if the insane survivability is a problem on ST its sure is the problem of AVRE aswell.
My point is, there should be a clear definition. Are we complain exclusively about ST without even looking at simular problematic behavior of AVRE, in other words: very high armor, relatively high mobility, very high HP and the nature of the unit.
Or we are complaining only about ST because it has more range and bigger explosion, therefore all of what I've mention before is a problem for ST alone, but completly fine on AVRE dispite AVRE having its own advantages over ST.
My possition is - I hate both ST and AVRE, but I think its a double standart to complain only about ST, since at least half of the problems ppl mention here apply to AVRE aswell. We objectively dont see AVRE that much only because other UKF commanders are usually much better to pick, while ST commander is not situational. Even in 1v1 221 alone provide OKW with really good AI unit to support Volks and in teamgames its the only way to boost resource income if you dont have Ost as a teammate.