Haha, yes, your soldiers feel that full fuel barrels are excellent initial cover and all they look like from above is something circular and metallic colored.
I agree with the using heavier tanks; the Panzer II I used against infantry I always hid in the rear on starting placement, behind buildings and used either as a long range unit against enemy infantry by ordering it to move fast from it's safe starting spot after I think I've found and taken out the AT guns or use it to peek out at infantry.
You are correct the halftracks were complete garbage in this game since the unarmored crew comparments allowed even basic rifle squads to kill them at long range. An exception is maybe the mortar and the Soviet rocket version, but that's because those could indirect fire.
I agree the snipers are not strong in this version, just slightly better than other editions I tried. I think the slow fire rate is a good thing as it keeps them from being targetted, suppressed, and then killed. The way I deployed them was similar to an MG team I'm planning to use for suppression and not use as an ambush unit for close range slaughter. The snipers didn't hit much, but once in a while when the enemy infantry squads are advancing with Move or Move Fast the sniper will take one out and make them lay down without being able to fire back at what hit them. Not great but there are a few early scenarios, especially early Soviet campaign, where you don't have many requisition points (like the very first opening scenario; I enjoyed when I could win or stall that one as Soviets due to it being pretty stacked against that side at that point with the Germans having tanks vs poor quality infantry. If you get the AT gun or AT Rifle team, can't remember if both were an option, you have enough for one sniper IIRC)
Did you find the use of AT guns? It turns out they are very sneaky and can hide in ambush mode until a tank comes arumbling into their view with it's flank facing them,, then I think I used to set them to Defend to have them open up. I think the big ones like the 88mm have a harder time hiding, but there are other large AT guns that fit into buildings that can disable most heavy armor tanks.
Flamethrowers are pretty great in effectiveness all around up until they hit their max range. I think the Soviets had a light or medium tank with a vehicle flamethrower that I used very often in the mid game. I think it was one of the BTs and not T-34, but I wouldn't be surprised both had flamethrower version. If you can get close enough without being disabled, it can kill heavy tanks with a few shots.
The Soviets' early war Heavy Tanks are great; the KV series for example. Panzer IV can't do much to it usually. There is one with a 152mm howitzer on it and I think 3 or 4 machine guns that is just silly. The craters it leaves on the map are great cover later on.
Another reason to use light tanks would be the sometimes mount a lot of machine guns. The Stuart lend lease the Soviets use mounts IIRC 3 or 4 on a speedy chassis. Another is they are somewhat speedy if the AI doesn't course correct too much (stoppig to overturn and then correct) and doesn't get stuck on terrain. I used them if there aren't AT guns and tanks that can kill them that I know of to take victory points sometimes since they are speedy but armored enough not to die to MGs. If they die or are disabled to one I missed, oh well I lost a light tank of questionable fighting power against other tanks. It is important to not rush the VP unless running out of time since bazookas and panzerschrecks. I sometimes shoot places I think infantry might hide with the main cannon and MGs, like a hedgerow along a road to a VP if I do have to rush it for time limits. If I don't have to rush I would move up slowly and get ready to give it a Move order to reverse it if anything happens. That's assuming no infantry are around to check it out first, due to the light tank's ability to speed across the map without every single unit being able to shoot it.
How did you set your scenario time limits? I think I usually did the highest setting but not unlimited, since rarely a true stalemate still occurs (you have one infantry left vs an immobile but still armed tank for example) and I'd prefer to let time run out then. That setting does seem to allow for more player victory as the player has time to advance the whole map if they do well instead of fighting several battles on the map like the default time limit would usually result in. Probably better the latter way imo but that time limit is a pita sometimes when you are winning a scenario like crazy but run out of time to take the last VP and they bring many tanks next scenario on that map.