Profile of Maret

I think, if don't make full redesign, and keep su-76 as it is, it should get pen buff (200-190-180 vet0 to 240-230-220 with vet) with vet and accuracy buff, to become mediums harcounter. While save initial 120 dmg. It make su-76 constant in AT damage against mediums and also make from it some sort of "reactive" unit and somehow justify drawbacks from decision to buil it. It still need 6 shots to kill p4 on any vet.

Reactive units are those you only ask if the other player has shown a clear strategy, I.e. mg spam, go for indirect fire. Infantry blobs, go for HMG and rocket arty. Panic puma was another example. SU76 fits this category right now

Because SU76 is already known to be a reactive unit, its worthless to mention it as a opening build kind of unit. Therefore the whole question lacks of sense.

It doesn't work even as reactive unit. If SU-76 will be in soviet T4 it could be reactive unit - "poor man" su-85. But in T3 it don't work in this role. I saw so many games when SU player lost T-70 in teller mine or pak. Almost no one build SU-76. What it shows? Why in desperate situations OST player make shrecks? Why even against P4 through T1 almost every player make backtech to zis?

I told it multiple time before:

1. If we want keep SU-76 in T3 it should change it's role to AI support tool
2. If we move it to T4 it could be reactive unit, as cheap hardcounter against P4. It could work.

I prefer 1-st way. Beacause 2-nd way IMHO will be much harder to balance.

Once more PG and Ostwind are a different case. Both unit are powered creeped to the point that they where UP.

SU-76 is a cost efficient unit.

Hell yea, time for magnificent stories. It was cost effective in old-times (with insane ROF and free barrage) when call-in meta was alive and you can call-in heavy. Bit it dead and smell like dead already long time.

My english sometimes failed me - what means "cost efficient" in your language? Because sometimes i think we talking in 2 different languages. In my language it's closer to - unit that for it's cost give you more value than it's cost. T-70 - cost effective unit in 9 minute? SU-76 in 9 minute? Will be su-76 cost effective in 13 minute when p4 will arrive (don;t forget about T4 delay in you can't call-in IS-2 until build T4)? How much it give to you field pressure in 9 or 13 minute? It will be cost effective if you start from T2?
Why almost every SU player from pros to someone who have brain - build 1-st unit in T3 - T-70 or make skip to fast T4? Why no one ever build SU-76? It not 1-st unit, not 2-nd, even not 3-rd.

Yes an ostheer player would absolutely use a unit like the su76 if it replaced the stug.

It means - never? How much you see SU SU-76 in games? How much you see SU-76 in pros games? OST players will never use such "sub TD" unit. If it will be call-in maybe, but not if you must make teching for this and pay such high price only for "zoning". You can build stug if you stuck in T3 and enemy push you by mediums or heavy. But you never build su-76 when you stuck in SU T3. Because ZIS.
Just imagine if in OST T2 will be SU-76 for 75 fuel cost. Do you ever will build it? For hardcounter this bloody t-70 as example? Answer - NO. You just delay your own core building and give enemy 3.5 minutes of freedom. Your P4 will arrive in this case only in 16-17 minute. You don't get field pressure like it was in case of 222 or flameht.
If SU-76 was in OST T3? For which targets? In T3 you could build 1-st SU-76 on 10 minute. You will trying to chase t-70? Or barraging SU maxims? In 11 minute you can build OSTWIND - hardcounter against t-70, stuart and really strong AI. Do you still think you need SU-76 in OST T3?

As for your suggestions:

I am against the first one as its too exploitable (eg enter the mode when the barrage is off cooldown, fire the barrage, then exit the mode) and a costless barrage on a cheap vehicle with AT as decent as the Su76 is not a good idea.

Your second suggestion... I'm not entirely sure how that's different than the current barrage unless you mean a direct fire barrage and I still dont know why it should be changed like that.

Your third suggestion has merit. Soviets have a severe lack of non doctrinal smoke options and a vet 1 smoke barrage could give it a lot of utility. I do however worry about the amount of smoke a pair of su76 could lay down at long range so if this is implemented, the smoke barrage would need a long cooldown.

AP rounds- While it's not horrible, I do not think the ability would be worth the micro tax or cost.

1. You will get movement and rotation penalty like su-85 after focus mode. AT of su-76 reduced to puma level as was wrote in the end (160-120-80 against current 180-170-160). And don't forget about microtasking. If enemy have at least 1 armor unit on the field, such "play" will be punished very hard. Or you when play for OST never catch up su-85 when focus mode just turn off?
2. It's the same as old barrage, just ability when you not in mode. You should have something when in not mode.
3. Smoke easy to balance - make the same range as for leig or pak howi.
4. AP rounds - don't make from su-76 cruel AT-hunter, but replace (in different way) ability of commander sight. You will get vision on armor unit that was hitted. It could help to zis-guns. Thats how support works. He just help his comrades do their job.

My main idea was give to player 2 viable start options on T3: t-70 or Su-76. If you opponent will make spam of su-76, how he supposed to fight with 1-st p4 ? And again su-76 will be more static, it will be better for defense, not for offense like T-70. You can't chase and wipe retreating squads. You also not get such useful ability as recon of T-70.

When SU player build T3 he could build t-70 or su-76 at 9 minute. At 13 minute 1-st p4 will arrive.
Average fuel income in 1vs1 +23 fuel (you have 1 fuel point and half of map). You think that 1 su-76 will get you more pain than T-70 rolling over battlefield and chasing your retreating squads? Yes, you can build 2-nd su-76 on 13 minute. But i think no one ever will try to do this. It will be very silly move.

When you have T4 you never ever want to build this su-76, you have katy with much more bigger range and wipe potential (and cost similar to su-76).
With such design it will not become exploitable.

Then that also applies to the StuG. Panther and pak 40 both are better at AT than StuG, just like su85 and zis are better at AT than su76.

Except of course the Su76 can engage at a safer distance, costs less and has an indirect fire option, while the StuG does more damage per shot and is more durable.

I can say with absolute certainty that if the StuG had the same stats as the su76, it would still get used.

As AT vs mediums stug works pretty well - always hit and always pen any stock medium, if don't move (say hi to Yuriy - he can miss to medium). It could be build in tier when player have all tools for game until the end. From SU T3 you can't play the whole game. Call-in meta was removed long-time ago and heavy call-in was removed also.

You want have in OST T3 squishy 400 hp unit with light armor and cost 75 fuel? Unit that only will be hardcounter to LV (stuart, t-70 or AEC)? But if you want have OST version, it chance to pen ally medium should be the same as for SU SU-76 pen OST medium (and you in that moment understand how silly looks, try to counter with LV hardcounter any mediums) and don't forget - 1 snare or flank from Stuart, T-70, AEC or AP-burst from USF M2 and it will be dead OST SU-76. Also don't forget bazookas, piats and ptrs they all will be pretty viable against so tiny-armored TD. Just 3 shots from atg or even from t-34/76 and you dead. -75 fuel. Any AT ability (SU AT arty, USF planes) also will kill any spam of su-76 pretty quick. Yes, you will get barrage (but OST mortar will be much more usefull IMHO) and maybe you will use it someday.

And again:
Stug - hardcounter vs any stock mediums, could fight against pershing and will be softcounter to is-2 or churchill. 2 Stug can keep at bay pershing or will be enough threat for other heavies.
SU-76 - hardcounter vs LV and softcounter vs mediums. Against heavies it even don't work if you build 2 SU-76 (even if you have 1 zis and 2 su-76 you will be in worse position against heavy than player with 2 stugs and 1 pak). Compare stug and su-76 tottaly wrong. They have only one common thing - both turretless.

Want try SU-76 spam against is-2, pershing or churchill?

Question 1: if you OST and can build SU-76 in T3 (or T2), in which situations you will be build it?
Question 2: if you SU and can build stug in T3, in which situations you will be build it? Answer: hardcounter against P4.

SU-76 just need to change role to AI support and it fully resolve this weirdy situation. AS like old ostwind become good AA and pretty strong AI.