Can you tell me the exploit you are talking about in more detail? Or are you talking about the AWS / GCP cpu abuse done by zean and others? If it is the second one, I dont think it appropriate to define it as a fundamental flaw of Arionum, but a flaw of the cloud services.
It was a flaw of the cloud services that was immediately identified by the general members and made visible to the dev team. An immediate update to the algo could have easily prevented the severe dump but they waited for months till the coin fell from a stable 1000 sat to lower 200 sat before implementing any change. To make matters worse, this wasn't a rewrite that needed several months to be implement rather its a week of work with a busy schedule, so it puzzles the shit out of me on why they waited to implement that change.