Heavier aircraft require new accelerators and arrestor gear

Would Courageous and Glorious need enlarged flight decks to operate aircraft such as Avenger or Hellcat?

Not principally for deck strength, but they would need upgraded accelerators and arrestor gear for heavier aircraft.

Deck strength was separate from the equipment that launched and recovered an aircraft. The existing flight deck was considered heavily built enough for larger types, so an increase in aircraft weight did not demand a wholly new deck structure. The limiting systems were the accelerators and arrestor cables, each rated for a particular weight range. A major wartime modernization would replace both, just as other carriers received stronger launch and recovery gear as aircraft grew heavier.