I've been trying to suggest a solution for a long time now. Allow escorts in WaW and subs will be balanced. Yes the CV can carry sonar (although it shouldn't) but how many CVs are up on the front line with the BBs?
The only recs on this thread are from those sub players that love shooting fish in a barrel and don't see anything wrong it. Well let's turn the tables shall we? Let's say that HH can shoot at BB range and all ships have sonar that can see all the way across the screen. Then make a room that subs can play in but BBs can't. BB players would understand why they aren't welcome, and I'd be willing to bet you wouldn't hear anything from SS drivers in that room about discrimination against BBs.