I think I found the reason why it is always the south side that gets beat, and never the other two.
For the NE side, the island which holds P203/CV204 is the ultimate defense line, probably the single most important base on the whole NE-NW front. As we know, usually the south side meets trouble when CVs crawl up to its left side - this, is practically impossible for the NE side. The left flank, is very harshly protected. By the port, and the CV spawning there.
Also, for the NW side, the northern shores only hold two accessible airfields from the sea, those two are more than 100 miles apart. Effectively, the chain of capturable bases, as seen at the left flank of the S country, is not seen in the NW country.
So.. I suggest:
1) Move the island holding P203 50 miles north.
2) Switch P160 and A162 position.
3) Remove the islands at 15.5 sector - major natural barrier which makes CVs inaccessible.
4) Switch position of A115 and P152. Since P152 will then be at inland, move it to the shore a bit.
5) Move A44 down 25 miles, to where P47 now stands.
6) Move P47 to a distant island, and make it a island base, preferably at 3.6.1