The next step: a 1923 British fast battleship with 18in guns

Last night, I designed the ultimate ship in the series of British fast battleships from 1905 to 1923. This ship is very compact in dimensions but has a full form, to achieve adequate strength. The speed is a modest 28 knots (faster than the Yamatos) and the armament is 9-18in, 16-6in, 6-4.7in AA, and 36-2pdr AA guns. The armour basis is 15in. The deck is a thick 8in. The ship seems to be small for the capabilities, so I wonder if there is some flaw that I am not seeing. This is the Springsharp report:

GB/BB/1923, Great Britain Battleship laid down 1923

Displacement:
 58,640 t light; 61,238 t standard; 66,000 t normal; 69,810 t full load

Dimensions: Length overall / water x beam x draught
 827.24 ft / 825.00 ft x 112.00 ft x 35.00 ft (normal load)
 252.14 m / 251.46 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, 1923 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority aft, 1 raised mount aft - superfiring
      16 - 6.00" / 152 mm guns (8x2 guns), 108.00lbs / 48.99kg shells, 1923 Model
   Quick firing guns in turrets (on barbettes)
   on side, evenly spread, 4 raised mounts
      6 - 4.70" / 119 mm guns in single mounts, 51.91lbs / 23.55kg shells, 1923 Model
   Anti-aircraft guns in deck mounts with hoists
   on side ends, evenly spread
      36 - 1.57" / 40.0 mm guns (9x4 guns), 1.95lbs / 0.89kg shells, 1923 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread
 Weight of broadside 28,354 lbs / 12,861 kg
 Shells per gun, main battery: 80

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 15.0" / 381 mm 540.00 ft / 164.59 m 16.00 ft / 4.88 m
 Ends: Unarmoured
   Main Belt covers 101 % of normal length

   - Torpedo Bulkhead:
  5.00" / 127 mm 540.00 ft / 164.59 m 31.00 ft / 9.45 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 15.0" / 381 mm 11.0" / 279 mm  15.0" / 381 mm
 2nd: 6.00" / 152 mm 6.00" / 152 mm  6.00" / 152 mm

   - Armour deck: 8.00" / 203 mm, Conning tower: 15.00" / 381 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 159,663 shp / 119,108 Kw = 29.00 kts
 Range 7,500nm at 18.00 kts
 Bunker at max displacement = 8,572 tons

Complement:
 2,058 - 2,676

Cost:
 £16.805 million / $67.219 million

Distribution of weights at normal displacement:
 Armament: 3,544 tons, 5.4 %
 Armour: 26,397 tons, 40.0 %
    - Belts: 5,608 tons, 8.5 %
    - Torpedo bulkhead: 3,097 tons, 4.7 %
    - Armament: 5,569 tons, 8.4 %
    - Armour Deck: 11,596 tons, 17.6 %
    - Conning Tower: 528 tons, 0.8 %
 Machinery: 5,336 tons, 8.1 %
 Hull, fittings & equipment: 23,362 tons, 35.4 %
 Fuel, ammunition & stores: 7,360 tons, 11.2 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   93,522 lbs / 42,421 Kg = 32.1 x 18.0 " / 457 mm shells or 16.1 torpedoes
 Stability (Unstable if below 1.00): 1.09
 Metacentric height 7.0 ft / 2.1 m
 Roll period: 17.8 seconds
 Steadiness - As gun platform (Average = 50 %): 54 %
   - Recoil effect (Restricted arc if above 1.00): 0.79
 Seaboat quality  (Average = 1.00): 1.09

Hull form characteristics:
 Hull has a flush deck
   and transom stern
 Block coefficient: 0.714
 Length to Beam Ratio: 7.37 : 1
 'Natural speed' for length: 32.88 kts
 Power going to wave formation at top speed: 53 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 4.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  32.00 ft / 9.75 m
    - Forecastle (20 %): 24.00 ft / 7.32 m
    - Mid (67 %):  24.00 ft / 7.32 m
    - Quarterdeck (15 %): 24.00 ft / 7.32 m
    - Stern:  24.00 ft / 7.32 m
    - Average freeboard: 24.64 ft / 7.51 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 81.0 %
  - Above water (accommodation/working, high = better): 174.0 %
 Waterplane Area: 78,348 Square feet or 7,279 Square metres
 Displacement factor (Displacement / loading): 101 %
 Structure weight / hull surface area: 224 lbs/sq ft or 1,091 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.24
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent