I think the reluctance to fit deck edge elevators in smaller CV designs has a lot to do with structural strength of the hull and the ability to continue to move aircraft to and from the hangar deck in rough seas. This was the reason that the British CVA-01 design of the 1960s had an aft deck edge elevator and a forward inboard unit. The new Spanish vessel has the same lift layout as the Pricipe de Asturias, suggesting it is a configuration the Spaniards are happy with, and her design was originally American! Based on Admiral Zumwalt's proposed Sea Control Ship design of the mid 70s, the only major change made by spain was to alter the bow to include a ski jump, so as fond of the deck edge lift as US designers are, they must have thought an inboard elevator was the right way to go for a small CV.
On a large CV/CVN the forward lifts are usually far enough back and high enough above sea level to avoid damage from 'slamming' in rough seas. On a smaller ship the forward lift would be closer to the bows and as the freeboard tends to be lower too (smaller CVs still tend to have hangar heights of 17'6" as opposed to a typical US large deck carrier's 25'), and large openings in the hull can cause weakness just where the ship is hitting the sea hardest. When HMS Hermes was fitted with a deck edge lift at the forward end of her angled deck during construction in the mid 50s, it's inclusion caused a lot of headaches for her designers who had to find ways of reinforcing the hull girder to maintain rigidity and special grades of steel had to be used. The smallest carriers fitted with deck edge units (to the best of my knowledge) were the US Iwo Jima class LPHs built in the 60s, and they mounted their lifts portside amidships and starboard side three quarters aft. Deck edge lifts free up internal volume in the hangar and thus increase aircraft capacity, no question, but the smaller the ship the more difficult their inclusion which is a pity as smaller ships would benefit most from increased internal volume.