How can you say that with any certainty? The Sea Spitfire was going to be a ground-up design, not a simple conversion like the Seafire as it eventually appeared. Not only that, the Seafire was not a bad naval fighter - careful you don't tread in that bias BS. The Seafire had an excellent rate of climb and was very manoeuvrable, with pilots reporting excellent control harmony and that it was easy to fly. It was, however, a mediocre deck-landing aircraft. Yes, it suffered accidents but someone on this site, and I can't remember whom or where, posted figures relating to deck accidents, and it turns out the Seafire's accident rate was about equal to other Allied deck aircraft, including US fighters, when comparing percentages. The alarm that Seafires initially caused on deck began during Operation Torch when sortie rates versus operational losses were skewed toward the latter, but progressive training in deck landing techniques sought to lower that attrition rate.