Schema there is still a problem you need to solve. You need to make hull more powerful
I think hull should benefit from having a hull block behind it. This would do 2 things, encourage thicker hull in critical places, and it would also make shooting a hull at an angle less effective. This is how armor works in real life anyway. The back armor strengthens the front armor by supporting it.
The way I think it could work (and this is going to require tweaking) The front plate gets a % increase from the hull behind it in armor, and an increase of half of that block's hp.
EG.
all blocks 50% armor, 100 hp
1 layer, normal
2 layers, 1st block 75%, 150 hp, second block 50% armor, 100 hp.
3 layers, 1st block, 87.5%, 175 hp, second block 75% 150hp, third, 50%, 100hp
4 layers, 1st block, 93.75% armor. 187 hp, second block 87.5% armor 150hp, third block 75% armor, 4th block 50% armor, 100hp.
Maximum of 4 layers benefit
any layers on top of that would have the 93% armor and 187 hp of the 4 layer armor.
Another thing to encourage hull is to give a slight armor benefit to shielding for having hull. This would also give rise to a new type of hull, one that has less physical armor, and more shielding armor. Maybe it would have regular hull qualities, but would add armor to shields a bit. This would give a disadvantage to nuke cubes in comparison. (my definition of nuke cubes is no hull, this should be changed to noob ships, since I don't consider a proper borg cube to be a "nuke cube")