Few things I'd like to comment on:
Opri spamming is retarded they can only fight villagers and buildings; anything else owns them. Use them in addition to your regular army.
Strelet spamming is hilarious but inneffective / inefficent it has won me many games against some decent players but it is still one of the stupidest thing you can do.
Strelets can be good in colonial just dont ever have more than 25. That way they can still kill villagers and stand a chance against other units. Mix them in with musketeers and cossacks and you will have a colonial age army that is not very easy to counter.
Grenadier rushing kills your economy do not try unless you are very experienced. (I even have trouble with it somtimes)
Fighting cannons with strelets is retarded. HOWEVER killing any infantry guarding it with them isn't so your cossacks etc. can get at them
Instant training infantry is great but it also means you have to be in industrial which is not a place you want to be in as russia.
A russian fast fortress is not the greatest but it is a viable option when you get to higher HC levels (10+).
GET COUNTER INFANTRY RIFLING FOR STRELETS THEY NEED IT!!!
FF does hurt the russians HOWEVER strelets counter heavy infantry you encounter with mercs and cossacks counter jagers so it is not unstoppable. (dont ask about black riders)
Hope that helped a bit any corrections please feel free to mention them.