Neither of them were prime at 155. But I'll say this. At WW Floyd would make it competitive but lose a UD. At 155 he gets stopped.
Leonard by KO, he would destroy Floyd. You need to put this together accurately. Floyd at 147 is not the same Floyd in any area as the Floyd at 130. Leonard was basically the 130 Floyd at 147. The higher the weight goes, the better Leonard's chances.
Any ATG discussion with Mayweather really should be contested at 130 (best) or 135. At anything 140 or higher, he'd be a clear underdog against any other ATG. This particular bout likely would result in a stoppage or else decisive decision for Leonard.