One thing I've always said (Well, not in this forum) that you can clearly see the doctrine different between US and Russia is Russia don't have Direct Penetration Helicopter (or DAPs) Russian army uses a combine of Mi-24 and Mi-8 or Mi-17 to bring air assault troop in battle, that would double the number of helicopter you need, plus, your Mi-24 weren't able to fire and cover the battlefield when all the Mi-8 is unloading. In the US, we use DAP Chopper like AH-60 to insert Air Assault Element into hostile environment. 4 AH-60 can land an entire platoon with 2 taking overwatch position when the 2 AH-60L unload, that way you only need 4 chopper to deliver an entire platoon of 43 men, if you use Mi24/Mi-8 mix, it will take you around 5 to 6 chopper and you need to be on station twice as long as you clean out your Mi-8, as they hold twice as many troop than a AH-60.
The reason behind this is that you don't need to wait for gunship cover during your insertion phase, because we operate a distributed firepower concept, which mean the once those AH-60 delivered those troop, they can act as a gunship, which mean whatever your ground troop see you can hit almost immediately, instead of having them to wait around for Apache or Viper gunship to come on station, by then it would be too late.
On the other hand, it's not like the Russian haven't thought about that, Mi-24 was created to do the same thing as DAP-60 blackhawk, albeit a bit less sophisticated, but with 8 seat and there are no way you can fit 8 fully armed and kit out soldier in it, they sort of abandoned that. It also worth notice that China also do not have such chopper in service, the biggest UH the Chinese have is Z-20. which is a copy of Blackhawk, and unless they can make PAVE or something similar to PAVE, the PLA Z_20 can't do DAP.