There’s no map of the war seas, dark seas, open seas or old sea. But TrollusRT created a map of the seven seas, so I recommend you check that out if you haven’t come across it already.
The seventh, fifth and fourth seas were all completely wiped out by Durza, who exploded into pure magic energy as a last resort to kill the Peacekeeper. What’s left of those three seas were all sent into space. The surviving four seas were plagued with colossal tsunamis and storms for decades. Extremely unpredictable weather, lots of droughts. Entire islands would go missing. The explosion’s initial shockwave even sent some sky islands falling into the sea, one of those sky island archipelagos likely being the racist town of Cerulea. In the now non-canon lore of WoM, the Peacekeeper lifted up the seafloor and filled it with life and vegetation, creating the continent of Magius, which sat on top of the seventh, fifth and fourth seas.