(this text is redundant with previous posts)
To my understanding, they are weak because they are not suited for combat, more focused on support and utility. I mean, their abilities can be absolutely broken on paper, like rewriting history, sending someone into oblivion, undoing any damage, gathering and sharing information, and of course boosting superhuman growth and copying/teaching others' techniques, but these have little to no effect on those stronger than or even equal to the the user, unless they have an exploitable weakness (like a trauma or stupidity), or they willfully subject themselves, meaning they en up relying on psycological warfare and hope, so they are better at the background.
Regarding the MC, his memory powers have increased his growth, helped him with faster and more accurate shape shifting, distracting/taunting Cole and so on, but yeah, he is only able to fully utilize them because of his physical powers, there is no use of increasing his Power tenfold to end up at 10 of a hundred needed. He could become a False Hydra or my best friend Tsukishima, but only when paired with another path, and even then they would work on the weaker targets.
A question about these powers, could the MC potentially revert monsterfication? Or would this be prevented by the same ethereal reason he can't copy powers with shapeshifting? (I believe Xanthe Sr. mentioned a while back that the MC could copy a monster's physique but not their powers due to the ethereal energies they use).
About our MC's weakness to lightning. What I gathered during Syla's fight with Indra is that it's psycological, not physical, meaning the Silats explode due to some sort of generational trauma, just searched on the wiki, its a traumatic event that translated into a physical reaction, and was transmited to her kin. Syla managed to overcome this by steeling herself and fully focusing on saving her family, so the MC could use this memory and lots of mental training to solve his problem, no physical modification can help.
And about superhuman aging. Apparently age seems to limit physical growth, I guess that if you are transformed at 9yo, you get a peak 9yo body, same with the teens, while if you are transformed at 86 yo, you would get a peak 20-30s yo body, because it would be the ideal one. Their body changes with evolution, so far I think we only have the orphans as examples, as they were infected when they were kids, I guess if the 9yo evolved at 12, he would transform accordingly. Still, I would like to ask about the lv5s, do you guys think they can de/age at will?