Breaking down your points
1. Yes, and it's problematic.
2. It isn't. Personally I find it less challenging than Langreskaya.
3. Doubt. Grens are marginally better than conscripts.
4. Mauls M3s, yes, can also be killed by 1 mine, an AT nade + small arms fire... the vet gain on it does seem too quick right now but other than that it's fine.
5. Except ZiS guns, mines and AT nades.
6. PAKs are pretty bad. ZiS is alright.
7. Protip: point the AT guns at the P-IV.
8. Not rewarded enough, yes; worthless, no.
9. ...
2. Semoskiy is better early game (thanks to the larger size of the map, the buildings and cover and generally very tight paths so mine kills can be relatively easy to score). It's worse than Langres late game for much the same reasons. On langres you need to survive until late game, on Semoskiy you need to win before late game. While maintaining a reasonable grip on the map in both scenarios.
3. It's not really even a marginal advantage, they very consistently beat conscripts in a straight out shootout (nevermind if the grenadiers pull out a riflenade). Occasionally lucking out and taking out a weak second squad like a combat engineer seems about on par.
4. Except after vet2. Also small arms fire is pretty ineffective against the scout car as they have a less than 10% chance to penetrate on any given attack. Think of how effective conscript dps is against an MG42 team, and then think what it would be like if they only did one tenth of it. Even if you land an at nade it can be extremely hard sometimes to kill the scout car if it was facing your way when it got atnaded because of the relatively high armor value.
5. & 6. As a Soviet player, I'd ALWAYS give a ZiS in order to get a PaK. The fabulous antitank ability on vet1 PaKs and the faster reload speed are both worth far more than the stupid munition sink ability on the ZiS.
7. Protip: Move PIV, it moves faster than the ZiS repositions. Also you can smoke if it looks like the ZiS might actually damage you.
8. It's pretty worthless because running a flank on an MG42 just puts you in the position where you now have to micro that conscript squad for the next 30 seconds-1 minute while avoiding the mg42 instant pin and several squad deaths that follow. It's still better than the alternative of just running into the arc and getting pinned, but considering the effort involved it doesn't really seem worth it to try and flank with 'scripts. Better leave it to penals and guards who can nade/satchel MG42s for a pretty much guaranteed kill.