winning a world series is special. At the time of the trade Kent had played 65 games. Sure he was a promising young player, but you didn't know exactly what you had. Cone came in and posted a 2.55 ERA the rest of the season with the Jays and the Jays won 3 of the 4 playoff games Cone started and won both of the world series games he started. Without Cone they may not have won the world series. Winning a world series trumps everything.
Kent posted a .770ish OPS in his years with the Mets. He didn't start posting hall of fame numbers until he was 30 to 39. If we had not made the trade the jays would have had a good young player developing who would have posted a .770ish OPS and then left via free agency. Those are definitely good numbers, but not hall of fame numbers. Those numbers would not have been the difference in the Jays making the playoffs from 94 to 99. We didn't trade a hall of famer for a rental. We traded a young player for a stud pitcher that quite likely put us over the top and gave us our first world series. Kent didn't become a hall of famer until his later years and he wouldn't have been a Jay anyways. The mets never made the post season with Kent in their lineup.