I'm not talking 2v2 btw because of the presence of a possible OKW ally giving them access to puma which hard counters the m5 and also if both are Ost they can each get 1 pak denying the effectiveness of the M5 which is to attack where there's no pak present.
Of course Ost will lose some level of map control. That's the entire point of a 'shock unit" like the M5, to swing map control to the soviets until Axis armor comes in. Another thing to point out is that Soviets don't have the luxury of your "fact". The fact is Soviets are forced to choose either T1 or T2 so that's either cons+support weapons or penals+snipers+cons, Soviets have to sacrifice either an effective infantry(penals) or support weapons to begin with. No one is going for both T1 and T2 unless they really need to or its already late in the game and is also contrary to the point of a fast M5 since T1 and T2 consts fuel thus it would delay T3 and ultimately the M5 if both were gotten.
Is Ost fighting an uphill battle when it comes to light vehicle? No one quite knows yet since the patch is still a week old and the meta has not yet stabilized, so until the meta has stabilized and majority of the top players think that T3 sov tech timing is broken it is assumed to be fine as is the opinion of the majority at the moment.
the only unit the sov will really miss is the sniper. Penal is replaceable by your choice of guard or shock, and the penal is hardly an "effective infantry" to begin with. The penal have worst dps than the
conscript >15 range.
soviet t2+t3 is hardly risky. There's almost no risk to using the quad m5 since it allow on field reinforcement as well. The only blind spot is the wehr sniper.
I am quite confident that t3 arrives too early, but the soviet is going to be put in a no win situation.
So good as the sov t3 is, it's still going to be at a disadvantage against the wehr t4.
There's no good way to properly time this new soviet t3. The ost just doesn't have the unit selection to present a good match for it. ost t2 is too weak for it but the ost t3 is too strong for it.
If the t3 timing get delayed, it's going to force the soviet player into situation where they are forced to fight panzer4 with su-76 with their t4 far ways away. The t34-76 and the su-85 are not exactly amazing units to begin with and having it early later than the pziv puts the soviet at a disadvantage. (guard motor is another thing entirely)
The new soviet tech tree make the t3 arrives too early and at the same time make the t4 arrives too late. Since any cost increase to t3 is going to inevitably delay t4 it's going to screw over the soviet. Unless they offset the increase to t3 with a cheaper t4 or make t3 entirely skippable.
Btw, Guard motor is still the best doctrine for the soviet, even if it's not as cheese after the nerf to guards and call in mechanic.