considering j0hn and larry's modifications seemed to be kind of 'exploratory' in terms of how they were relevant to Order's studies, and j0hn has features from Order's tampering which go on to sort of be iterated on with the clonebot line of experiments, i think the mach line was meant to be something similar for the type of modifications larry has, but she struggled to recreate what Larry's got going on in the same way. Machiavelli, an ultimate lifeform, the Ultimate Fighter, is described as being built to learn and adapt, even physically, to copy new opponents strengths to use against them, which is the explanation for his kirby copy ability- and presumably also like, his down b where he turns to stone/metal and comes crashing down- he's a copycat learning machine, whose form can change in a seemingly limited (although whether thats a hard limitation or simply a hurdle he hasnt gotten over yet is unclear,) way to facilitate adapting new techniques. This is an ability which mach 2 appears to entirely lack, which may be part of why Order had such disdain for him as a 'failed successor.'
Most of this assumption comes from kirby copy ability and also this bit where Machi thinks Larry wouldve been a better fit to be the ultimate fighter because he's shifty 'all the time,' implying thats something that wouldve been desirable in achieving the goal he was designed for as the Ultimate Fighter™.