Use of certain tanks

I have a question considering tanks in CoH2. I'm ranked 64 now and I noticed that I only use a couple of the tanks the game gives me access to, which made me wonder; Are the tanks I don't use completely useless, or I am not using them as I should...
Here is a list of the tanks I rarely or never use.

Soviet tanks:

T-70: Used to spam this one before the patch, no longer see any use in it. Rarely see it being used.

T34/76 Medium Tank: Used to use this a lot in the beta and post-launch, but recently I'm skipping the entire T3, and go straight for SU-85.

SU-76M Assault Gun: I only use this as a call-in from the command tree when I'm going for a conscript spam-like strategy (use nothing but cons and called-in guards rifles to gain map control, build no buildings (perhaps sniper if deemed necessary) and than call in these tanks.)

Ostheer tanks:

StuG III Ausf. G Assault Gun: Never used it, go straight for P4 instead.

Flakpanzer IV Ostwind: Never used it.

Sturmpanzer IV Assault Gun: Never used it.

My question is this: do these tanks really have use in the game as it is now? I seem to be able to snatch quite a lot of victories (though losses are no stranger to me) without using any of these. Do you use them? If so, when and how?

Cheers!

i have used all units but brummbar. they all fit into an specific strategy i use.

Since the patch I've been using T34's more. Reason is I find the Panzer less of an infantry threat so less worried about it, plus if I'm cornered by a Panzer I just ram it. And it's good to attack with, especially against unupgraded PGrens and MG's. Don't think I've even touched an SU for like 20 odd games and not done bad.

I also use artillery trucks and scout cars but any other vehicle I tend to never need.

edit: And as Germans I always get an Ostwind out early. It's a meat grinder.

@Godz_Mercenary

Ramming a Panzer may disable it for a while, you still need some punch to take it out. Do you rely just on guards rifles, at guns etc to deal with in once it's immobile? Because if the panzer is guarded by infantry, which it should be, that could become a problem. Also, the German tanks have a decent speed when their engine is damaged, making it able to get out of the hot-zone before your T34 does.

Yesterday I played a game, where I finally saw the use of T3, after T4. I had 2 SU-85s and was using them to deny the enemy any access to a certain part of the map. However, the enemy didn't advance for a while, nor did I. When he did advance, he had Tigers (should've seen that one coming). At that point, I could've won using T34s to ram them, but it wasn't to be. Maybe using them as a call-in would be ideal.

I am going to have a better look at the Ostwind next time I play Ostheer.

@Undostrescuatro

Perhaps I should look into some new techniques, using the full range of tanks in the game.

Here it is

t-70 ... i hate this tank (when playing as ostheer) it just violates and rapes me in the a** , its accuracy and ROF is madness and it can crush troops as well, ive lost games 3minutes after he comes in :<
Soviet usually rush it , or if i have p4 on the field they rush to cripple my panzer and go into my base with t-70 (consider every unit that retreats to be dead , no escape!)

t-34/76 good tank if you have AT guns or guards, it rly needs AT units with it cuz it sucks that way, its awesome vs AI + great speed
If you want to fight tanks with it u must mass it , only engage when u have number advantage

SU-76M great assault gun, cheap , nice barrage takes out light vehicles and can support in engagement vs medium ones, again barrage ability is sooo good (good for taking out crew weapons, especially PAKS) works great with SU-85 imo

Ostwind ultimate infantry reaper , its just so powerful and mobile at taking out any infantry and light vehicles! (i use it more lately since panzer4 AI capability has deteriorated)

Stug III Ausf. G well this is one tank i dont use , i would gladly save up for panzer4 if fighting tanks cuz if stug gets AT naded say good bye, and SU-85 has superior range so no point in making Stug if he does in 3 shots + its AI capability is not that good... Imo this tank is only good if you want tank rush to destroy light vehicles and is only great when it has veteran ability (stun) when supporting your tanks in engagement

Cheers

Thanks MadrRasha!

T-70: Seems I've been using that one too kindly Going to try to use it with more aggression next time. I've always been holding it back, figuring it doesn't stand much of a chance due to low armor value.

T-34: I know how to use this one, I know it's not meant to take on an enemy tank alone, but apart from that game I mentioned earlier on, I never had a feeling I needed them. Rushing SU-85s seemed like a more valid strategy, until I met the Tiger response

SU-76M: I confused this tank with the heavy assault call-in However, the SU-76M could be a replacement for my ow so beloved 120mm Heavy Mortar.

Ostwind: Like I said, going to try to use this one more often.

Stug III: I have a feeling most players skip this one all together.

Stug is actually decent when your opponent has t3 up and you have the upperhand on infantry battles.
But when does that happen

It's rotation speed and speed in general is not good enough to keep dodging atnades.
Stun is awesome though. But what I hate about this it can actually miss