I saw some discussion regarding the disparity of costs between armour and weapon ship parts. For example, as commented by afwbkbc

here.

I wonder if he is right about best design being 1 weapon and rest of external slots for armor.

Some scenarios for self-gravitating (6 ext. slot) hull. I'll be using the values I get from an advanced game (turn 285, full tech researched, 4.5 PPs and 1.5 RPs), but I guess that does not matter as cost increases are proportional for every ship part.

Model A: Self-grav. with 1 x D.R., 5 x N.A., structure=300, dmg=30, cost=608.5

Model B: Self-grav. with 5 x D.R., 1 x N.A., structure=140, dmg=150, cost=1170 (92% more than model A)

If we pitch 2 model A against 1 model B we get:

Assuming worst luck for model B (i.e. alternating hits between the two enemies)

Round 1:

A1 and A2 do 60 dmg to B (80 left)

B does 90 dmg to A1 (210 left) and 60 dmg to A2 (230 left)

Round 2:

A1 and A2 do 60 dmg to B (20 left)

B does 60 dmg to A1 (150 left) and 90 dmg to A2 (150 left)

Round 3:

A1 and A2 do 60 dmg to B (destroyed)

B does 90 dmg to A1 (60 left) and 60 dmg to A2 (90 left)So armored model (A) beat armed model (B).

Assuming best luck for model B (i.e. focusing on one enemy)

Round 1:

A1 and A2 do 60 dmg to B (80 left)

B does 150 dmg to A1 (150 left)

Round 2:

A1 and A2 do 60 dmg to B (20 left)

B does 150 dmg to A1 (destroyed)

Round 1:

A2 does 30 dmg to B (destroyed)

B does 150 dmg to A2 (150 left)So again armored model beat armed model (B).

If we add the best shield to this and misiorla pilots, things stay the same. If we add just the shields (15 strength), the DRs get severely handicapped but that goes true for both models:

Assuming best luck for model B (i.e. focusing on one enemy)

Round 1:

A1 and A2 do 30 dmg to B (110 left)

B does 75 dmg to A1 (225 left)

Round 2:

A1 and A2 do 30 dmg to B (80 left)

B does 75 dmg to A1 (150)

Round 3:

A1 and A2 do 30 dmg to B (50 left)

B does 75 dmg to A1 (75 left)

Round 4 (1 of next turn, no repairings):

A1 and A2 do 30 dmg to B (20 left)

B does 75 dmg to A1 (destroyed)

Round 5:

A2 do 15 dmg to B (5 left)

B does 75 dmg to A2 (225 left)

Round 6:

A2 do 15 dmg to B (6 left)

B does 75 dmg to A2 (150 left)So it seems shields do not change the advantage that armored model has.

Model C: Self-grav. with 3 x D.R., 3 x N.A., structure=220, dmg=90, cost=888.7 (42% more than model A)

Two model C vs three model A:

Assuming focused fire and black shields:

Round 1:

Cs do 90 to A1 (210 left)

As do 45 to C1 (175 left)

Round 2:

Cs do 90 to A1 (120 left)

As do 45 to C1 (130 left)

Round 3:

Cs do 90 to A1 (30 left)

As do 45 to C1 (85 left)

Round 4:

Cs do 90 to A1 (destroyed plus 60 dmg wasted)

As do 45 to C1 (40 left)

Round 5:

Cs do 90 to A2 (210 left)

A2 and A3 do 30 to C1 (10 left)

Round 6:

Cs do 90 to A2 (120 left)

A2 and A3 do 30 to C1 (destroyed and 20 dmg wasted)

Round 7:

C2 does 45 to A2 (75 left)

A2 and A3 do 30 to C2 (190 left)

Round 8:

C2 does 45 to A2 (30 left)

A2 and A3 do 30 to C2 (160 left)

Round 9:

C2 does 45 to A2 (destroyed and one shot of 15 dmg wasted)

A2 and A3 do 30 to C2 (130 left)

Round 10:

C2 does 45 to A3 (255 left)

A3 does 15 to C2 (185 left)

...

Round 16 (turn 8 ):

C2 does 45 to A3 (destroyed and one shot of 15 dmg wasted)

A3 does 15 to C2 (95 left)So model C (half armour and half weapons) beats the armored model.

1 model B costing 30% more than model C, would have a bad time to beat it, staying alive with 5 structure after round 3.

Therefore, if we leave aside stealth, fighters and auto-repairs, the armour/weapon balanced design beats the extreme designs. I'm gonna assume this remains true for bigger hulls.

In the end, it seems armour prices do not need any balancing. I find it rather good.