If Plato and Aristotle wish to maintain the status quo, then such a system is just the thing that is needed.
"Sufficient" doesn't carry it. "Ideal" gets closer. What word captures "just the thing" or "exactly what is needed"?
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Very thing is the very thing for you.
Exactly what is needed or wanted, as in That hat's the very thing to complete the costume. This idiom, which uses very to denote exact identity, was first recorded in 1768.
If you're willing to accept a phrase, consider the idiom "That's the ticket!"
If it is a high register I would consider using ad hoc. It's cult, but I don't think it to be strictly formal, though - it seems to refer to a solution purposely intended for the problem, rather than an optimal solution found at random.
Grammar tip: in English it works as an adjective - that is the ad hoc system.