These campaigns are severely depreciated. One amusing note is that in at least one of them you can get 2 different KV-1's, the single-player version can be built from the tank factory while the multiplayer version can be called in. Now that the MP version is tied to tech, I can't confirm whether or not it's still available in ToW.
The ToW in general seem to have some odd balance issues, I remember at least one of them just relentlessly threw units at you (that the AI gets free in bulk from off-map, in addition to the ones it builds) and it was nearly impossible to beat by playing fair. Me and my friend beat it after many attempts by ignoring the objectives and destroying their HQ.
Well, in total i can see four units, which are easily replaced with their better copy from MP:
1. KV-1 - you can have both versions at the same time. SP one cheaper in fuel and less efficient against infantry, MP one is cheaper in manpower, but much more expensive in fuel.
2. StuG E - you can have both versions. MP one is better in all aspects, except fuel price.
3. Panzer F1 - can be replaced by Panzer J with the newest doctrine.
4. PAnzergreandiers with MP 40. You can get Stormtroopers or Assault grenadiers with better MP 40 for same/lower price. Stormtroopers additionaly can get panzerschreck.
Yeah, the greatest issue at the moment in ToWs is that you can acces certain equipment and vehicles that were not available at the time of the mission, most notably the ostheer puma, panzer iv j and stormtrooper schrecks.
And yes, panzergrens in ToW are terrible.
Also, in some missions AI and player intended to have some stuff, which they can't have in 1941 or 1942. Like you can get IS-2 ace in Stalingrad 3v4 coop mission, or germans have panzerschrecks, pak 43 and panthers in at least one of 1942 missions.
Also, not sure if intended, but Faceoff at Rostov is unreasonably hard. Whenever the player team holds more victory points than the enemy the ai gets large amount, usually veteran reinforcements instantly that just mows down any defenses you have. Leaving base rushing right from the start the most viable option to win that particular mission.
I've completed this mission with close the pocket, and my mate played with Puma and defence on island. They have 1 cutoff, so it's pretty easy to capture it and click the ability.
On the partisan bridge defense mission (apart from being very hard by the end if you don't discover that there are abandoned AT guns on the map, lol) it is possible to fully repair the panzer 4 (the one that initally has only the pintle mg functional). If you are lucky the enemy pios will even help with repairing it.
IMO it's intended, since you pay munition for each repair. Also, this panzer sometimes can be randomly abandon with almost full health, pretty annoying. And it get -50% health, if you fully repair it and after that recrew for the first time. I think the issue in that mission, that you have mixed early SP and very late MP things in one place. Probably it wasn't intended.