About doctrines, as I wrote in the 1vs1 balance thread in the eSports forum, yes you need a doctrine when you play Russians vs a competent opponent, and this is also part of the reason because they are stronger than the German ones. Germans simply do not rely on them that much and they have a minor impact on your gameplay (compared to the Russian ones at least).
In my experience you can play 1vs1 both relying on an MG or by simply spamming Grenadiers. MGs are better than their COH equivalent, they switch targets instantly and they do overall more damage (pinned units start received increased damage after a few seconds now). On the other side, TrueSight and ColdTech, as well as smoke being useful now, made MGs less viable. I never get more than one and I usually rely on a strong T1-T2 strategy (3grens,mg,mortar,sniper->T2) to ensure I have a good number of early game units on the field to stop Russian power in the first minutes.
As I said molotovs are ok, but the animation of the guy throwing the molotov takes a lot more time than vCOH (you will notice the difference if you call a special infantry unit like Shock Troops and Guards and try using their grenades), so yeah a decent opponent will most likely dodge them. More than that I feel like those 25 fuel are spent better to get the first M3A1. The M3A1 is not that strong as it was before, but it's cheap and it offers a lot of mobility around the map, you can use snipers/engineers/guards inside to counter infantry/MGs and garrisoned units/light vehicles. For me it has the same impact an M8 could have in COH. But again, having played on the other side too I can assure you it's nothing that hard too counter.
Vs buildings flames, molotovs, grenades, ATs, tanks but more than that grenadiers grenade launcher and mortars are the best way to clean them. You have to aim the exact window where you want to throw the grenade, it affects the damage dealt by a lot, especially molotovs. (pretty much like in coh, but if you don't aim correctly in COH2 you may cause less to no damage at all). Units still attack faster the closer you get to your target as in COH.
A T34 is the medium tank you've built, it's a worse Sherman more or less, which I found more consistant vs infantry. The small tank you built was the T-70 and it's like the old American T17, capable of shooting very fast, good vs light vehicles and infantry.
The effectiveness of small arms fire on the scout car and the halftrack right now is: scout car feels more or less like PE scout car, halftrack feels to be something between a scout car when you use the ability to secure a point and a Puma. You won't kill it with normal fire usually, but if it's left with few HP small arms fire will do the job.
On a side note: the frontal MG of the M3A1 does penetrate the armor of the Halftrack like butter
For the rest, yes play more and experience these things yourself
