If we think of ourselves as real pilots in a real war, where concern #1 for the pilot is to not die, and attrition of enemy pilots is a factor, then kill/loss ratios become paramount and a the single greatest factor in having a positive kill/loss ratio is the ability to engage when you wish and disengage when you don't, IOW, speed. By that standard, the SpitXIV would be clearly superior to the SpitXVI.
However, we are not real pilots in a real war with real objectives, we are playing a game for fun. Attrition is meaningless in the MA, K/D ratio is only one of several factors a fighter score is based on, and flying in such a way as to possibly a get a kill every once in awhile while insuring RTB is no one's, or at least very few people's idea of fun.
So, while the SpitXIV obviously has the potential to maintain a higher k/d than the SpitXVI because of its speed, the SpitXVI pilot, blessed with superior turn, superior roll, and superior handling, clearly has the potential to kill more often (higher k/t), more times per sortie (higher k/s), probably hit what he aims at more often (higher %), and will do so with more ease (higher "fun" factor).
So, if we reject the fallacy of judging the airplanes as if we were flying a hit-in-run style in a real war with kill/loss ratio as the primary goal and attrition as a factor, it becomes far less clear which is the superior MA airplane.