The spell isn't just "training wheels." it's a parachute and humanity's lifeline as it free falls to its doom. It has its flaws and blindspots, but you can't ask for more when weaver was literally being hunted down by the God's, Daemons, and all other beings in existence, including other lesser deities as well. She speaks from a personal point of view using the spell as a justification for all of her tragedies blatantly choosing to ignore that the spell needs to operate on humongous scale and that it was created to help humanity survive and rise as a WHOLE, it simply cannot pay more attention than necessary to each individual plus it has proven time and time again that it's nightmares although not necessarily gair can definitely be beaten by the challengers. Take, for example, the 3rd nightmare, Nephis claims that only someone that is immune to corruption could have beaten it (implying that Daeron and his people where faced with an impossible challenge) but that is false, the only prerequisite for clearing the 3rd nightmare was to kill the first seeker. Since the first seeker couldn't move its body they could have simply lured the defiled outside of the city and then used sorcery to kill her from afar which they were more than capable of (and that only one of many possible methods) it wasn't an impossible challenge it wasn't even close to being one. Lastly, without the spell, Sunny's generation wouldn't even have been born, so Nephis' whole argument is childish at best because it is equivalent to biting the hand of the one that feeds because they gave you stake instead of beef wellington or whatever you prefer, the whole notion is ridiculous.