All grenades are different. Actually on average, the German grenades are stronger. I think Soviet grenades just happen to be more plentiful. Guess it's a case of the grass is always greener on the other side, or perhaps it's the snow is always whiter?
Shock Troop grenades seem to be the same as Guards, but even if they're not, I think the reason why they seem stronger is that, much like PG grenades, Shocks and PGs do a lot of damage as they close in to grenade range, and continue to do after the grenade detonates.
Grenades work strangely in CoH2 in that, if you use them on a squad with no and very little damage on them, it seems to do nothing, even the health bar doesn't seem to budge. But, if you use a grenade on a unit with 1/4 or more of its health gone (ideally at least 1/2) the grenade will usually kill quite a few, or wipe the squad. This has a bit to do with criticals, I think.
This lets those close assault units like PGs and Shocks quickly apply that initial damage, which makes grenades more effective, then continue to apply damage to finish them off.
The same is true of the rifle grenade, which people like to laugh at, but I find is an effective finisher, or a starter.
Guards can probably stay at 1 CP, if they lose their initial AT Rifles, which become an upgrade once you meet some kind of requirement.
I love the German light vehicle play, even though I'm a primarily Soviet player, I love seeing those things used. So I'm fine with more adjustments to make those vehicles viable for a long time. However, the M3 Scout Car should also get the same treatment.
Shock Troops I'm just not sure to do with them. They're supposed to be breakthrough troops, based on the Engineer Sapper battalions used to break through German fortified lines. They're the kind of unit you use when German infantry get too upgraded. Because despite what German players say, German infantry can get to a critical mass that can wipe conscripts just as fast as artillery can kill the small German units. So 2 CP should be fine.