the long and short is being able to remove enemy cover is giant and should not be freely available without any realy tactical though in using it. torching cover is huge because it not only removes the defensive bonuses of cover but if it makes the enemy miove, they will lose dps as well.
combined with units like mgs that need to pack up, and especially the maxim who is prone to deathlooping its not great for balance.
Sturms sort of are overloaded, even early. OKW are already reliant on them to assault and push away enemy infantry, deny cover (Through their slow Barbed wire), are the only source of Healing for OKW if they don't go BGHQ (and if they do this they're not likely to have a ton of Muni for STGs and Incendiaries) and repair the ultralights that OKW is likely to have early (The 221 or Kubel). They're also the only engineer squad that you really can't justify having multiple of, given their price/performance (later on) and their popcap.
I don't think they're a good candidate for being OKW's only source of anti-structure/anti-cover early on, as-is. Perhaps if they had a change someone else suggested, initially having MP40s, being 5pop, having access to a flamer upgrade by default (And having the option to upgrade to STGs to become precisely the same unit they are now, the initial sturm would remain pre-upgraded) then it might make sense, but it really doesnt right now. Limiting OKW access to fire EVEN FURTHER with no real compensation is an unjustifiable nerf.
Vet2 offsets it due to other surrounding factors, as mentioned. The fact that SOV get the best flamethrower squad in the game (Thanks to Merge), the fact they have oorah, and the fact that they simply have OPTIONS, whereas OKW does not. OKW's flame nade being somewhat stronger than SOVs really is fine. UKFs grenade is better than USFs (Until vet, then USF have a range advantage, though their grenade is still more expensive and has a longer fuse), despite being even closer in functionality than Molo and Incendiary. Tools a faction has do not need to be exactly the same, given that each faction has their own strengths.
Conscripts should perhaps not have to pay so much for AT grenades and Molotovs, but given that, again, SOV have options in the anticover category, and they have a nondoctrinal sprint, it's difficult to justify them getting it for "free" like OKW do. Incidentally, Oorah isnt 20 munitions, it's 15. You end up spending 5 munitions more to sprint around and then throw your molotov. Your desire for a cheaper throwable is already the case. Also: I keep reiterating this, but OKW may have no choice but to frontally charge an MG that SOV could instead have a mortar smoke out, given that SOV can actually build a mortar early. This isn't even mentioning that if you're playing against OKW as Soviet you won't be facing MGs early game, whereas if they face you they very well could be.
Comparing the performance of Grens and Volks directly against Cons doesn't really mean much. OST has their MG to back up Grenadiers, OKW does not. The drawback, again, is the fact that OKW are very limited in what they can field early. They're the only faction without an early AI team weapon, and only one of two without a (practically) out-of-the-gate MG option.
Are you really outnumbered/outgunned early against OKW as Sov? Cons are fairly comparable in performance to Volks despite being significantly cheaper in both cost and reinforcement. Sturms are the confounding factor, but they're very expensive themselves, and if you manage to avoid getting ambushed you can make favourable trades against them, particularly if you focus them with multiple squads.
I can't comment on Sander's changes in this context, they're still evolving.