The US/BB/1937 design seems too good to be true

To my jaundiced eyes, the US/BB/1937 design seems to be too good to be true. The ship has a higher speed than the Yamato and carries a good (for 1937) AA armament. Admittedly, the armour basis is "only" 17 inches. The main improvements over the previous design are thicker armour deck and anti-torpedo bulkhead. There is a modest increase of the light AA armament. This is the Springsharp report:

US/BB/1937, United States Battleship laid down 1937

Displacement:
 61,913 t light; 64,708 t standard; 69,500 t normal; 73,333 t full load

Dimensions: Length overall / water x beam x draught
 860.80 ft / 855.00 ft x 112.00 ft x 35.00 ft (normal load)
 262.37 m / 260.60 m x 34.14 m  x 10.67 m

Armament:
      9 - 18.00" / 457 mm guns (3x3 guns), 2,916.00lbs / 1,322.68kg shells, 1937 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      24 - 5.00" / 127 mm guns (12x2 guns), 62.50lbs / 28.35kg shells, 1937 Model
   Dual purpose guns in turrets (on barbettes)
   on side, all amidships, 4 raised mounts - superfiring
      42 - 1.10" / 27.9 mm guns (9 mounts), 0.67lbs / 0.30kg shells, 1937 Model
   Anti-aircraft guns in deck mounts with hoists
   on side, all amidships, 7 raised mounts - superfiring
      40 - 0.50" / 12.7 mm guns (32 mounts), 0.06lbs / 0.03kg shells, 1937 Model
   Machine guns in deck mounts 
   on side, evenly spread, 32 raised mounts
 Weight of broadside 27,774 lbs / 12,598 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 17.0" / 432 mm 600.00 ft / 182.88 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 108 % of normal length

   - Torpedo Bulkhead:
  6.00" / 152 mm 600.00 ft / 182.88 m 32.00 ft / 9.75 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 17.0" / 432 mm 12.0" / 305 mm  17.0" / 432 mm
 2nd: 2.00" / 51 mm 2.00" / 51 mm  2.00" / 51 mm

   - Armour deck: 8.00" / 203 mm, Conning tower: 17.00" / 432 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 185,957 shp / 138,724 Kw = 29.00 kts
 Range 12,000nm at 15.00 kts
 Bunker at max displacement = 8,625 tons

Complement:
 2,139 - 2,782

Cost:
 £31.663 million / $126.651 million

Distribution of weights at normal displacement:
 Armament: 3,472 tons, 5.0 %
 Armour: 29,472 tons, 42.4 %
    - Belts: 7,378 tons, 10.6 %
    - Torpedo bulkhead: 4,262 tons, 6.1 %
    - Armament: 5,590 tons, 8.0 %
    - Armour Deck: 11,622 tons, 16.7 %
    - Conning Tower: 619 tons, 0.9 %
 Machinery: 5,154 tons, 7.4 %
 Hull, fittings & equipment: 23,815 tons, 34.3 %
 Fuel, ammunition & stores: 7,587 tons, 10.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   107,231 lbs / 48,639 Kg = 36.8 x 18.0 " / 457 mm shells or 20.4 torpedoes
 Stability (Unstable if below 1.00): 1.12
 Metacentric height 7.3 ft / 2.2 m
 Roll period: 17.4 seconds
 Steadiness - As gun platform (Average = 50 %): 52 %
   - Recoil effect (Restricted arc if above 1.00): 0.76
 Seaboat quality  (Average = 1.00): 1.05

Hull form characteristics:
 Hull has low forecastle
 Block coefficient: 0.726
 Length to Beam Ratio: 7.63 : 1
 'Natural speed' for length: 29.24 kts
 Power going to wave formation at top speed: 52 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 5.00 degrees
 Stern overhang: 3.00 ft / 0.91 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  32.00 ft / 9.75 m
    - Forecastle (20 %): 1.00 ft / 0.30 m (25.00 ft / 7.62 m aft of break)
    - Mid (50 %):  25.00 ft / 7.62 m
    - Quarterdeck (15 %): 25.00 ft / 7.62 m
    - Stern:  25.00 ft / 7.62 m
    - Average freeboard: 22.68 ft / 6.91 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 75.4 %
  - Above water (accommodation/working, high = better): 174.8 %
 Waterplane Area: 78,525 Square feet or 7,295 Square metres
 Displacement factor (Displacement / loading): 103 %
 Structure weight / hull surface area: 224 lbs/sq ft or 1,096 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.99
  - Longitudinal: 1.07
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent