Believe me mate, japanese escorts aren't dumb....they have sonar and they know how to use it. the problem is that until mid late 43, they set their search and depth charges until 200 feets maximum since they touugh this is the max operating depth of the american subs (really, historically they did that often, not ever, but often), and often they didnt even create convoys without protecting their merchants ships (there was few destroyers) after mid late 43 when they create the grand escort fleet and know via american press (fault of an american politician who told that to the journalists) that american subs was safe under 200 250 feets, they start to create the grand escort fleet, building many small corvettes and sub chasers with specialized anti submarine crews, and the american submarine losses raised drammatically (the wahoo, the harder and other subs was lost in that way, late in the war the last two years the japanese escorts become tough guys).
So early in the war you will meet unexperienced escorts usually (but there are some experienced like when you read destroyer escort or subchaser CH etc etc, there you must be careful, they could be elite crews specialized in asw, and once they chaught you with sonar they don't loose you and every bomb is near than the previous!) but late in the war they will become tough guys coordinated with the air forces too (the MAD SENSORS! THAT IN A FEW MODS ARE EVEN REPRODUCTED I GUESS).
AS I SAY EVER IN SH4 TO THOSE WHO COMPLAIN ABOUT JAPANESE ESCORTS IS THAT: THEY ARE EASY AND UNCAPABLE UNTIL THEY DON'T KILL YOU. JUST ONE BOMB DROPPED IN THE RIGHT POINT, AND YOU'RE FOOD FOR FISH
If you raise their capability, late in the war you will find unrealistic war machines with a laser pointed on you, not a sonar (like in the old tmo under certain conditions). So instead is realistic and historical. Early in the war you will meet mostly unexperienced escorts, late you will meet specialized hunter killer groups especially the kaibokan on the route of the philipines, and minefields in south west asia and around japan! the sea of japan is a trap in late 43.
Have more respect of them my friends, since they're dumb until they don't kill you.
maybe they aren't the royal navy in atlantic, or the italian torpedo boats and corvettes on thge routes for lybia, or the german asw vessels in the baltic and black sea (each of these in atlantic, mediterranean and baltic killed a lot of subs, but the champions was the british very specialized sub killers), but they are pretty capable to chase and kill you on the right conditions, and late in the war they will become tough guys, i garantee.