I find it very annoying that the percentage value of the progenitor is based on rng. I'm generally not a fan of rng and especially not for items that require a lot of farming. It leads to disappointment and frustration when a progenitor roll is low and you know you have to do all that stuff again to improve the value. I think these kinds of systems are outdated and don't promote a positive gaming experience.
I realize that there are a lot of players who don't mind chasing the same carrot over and over again, but that doesn't mean it's a good concept.
Some will probably say “you don't need a weapon with maximum progenitor value”, which may be all well and good, but the thought remains in the back of your mind that the weapon you farm doesn't have the maximum value but the minimum or just above the minimum value.
However, since people always hope to get the greatest possible return for the time or work they spend, RNG systems leave a negative aftertaste that negatively affects the fun of the game in such moments.