I have a feeling that a lot of people will quit WoWs because of submarines in Random Battles. Same thing happened to WoT when they opened the door to cars, WG didn't learn their lesson it seems.
Imagine playing a BB and 3 enemy DDs, 1 CV, 1 Dutch cruiser with airstrike, 1 cruiser hidden in the mist (firing HE with fire starting abilities that exceed 50%) and 2 subs are after you and you cannot see any of them, sound like fun. yeah, REAL FUN.
What is the next step of "realism"? Naval mines? Gun batteries firing from the shores? V2 rockets? Laser beams from the sky? Sometimes less is more ..
Instead of submarines, WG should make MM more balanced, limit the amount of 2-tier-difference battles a player has ( they say 8/20 battles are against +2 tier enemies, but if you keep a record, they are more), reduce the dpm some cruisers do and their ability to start fires ( in some cases 1 every 3 shots starts a fire), fix the RNG factor that make a cruiser showing her citadel, taking an AP salvo from a BB , taking 1050hp damage.
There are many things that decrease gaming experience should be fixed first, but does WG care about it's clients??