The entire problem is the very nature of thresholds. Again, the algorithm itself could care less if the format is "good" or "fun" or well, anything.
Pillerfield Ox is no more or less important than
Underground Sea. Is that also the case for players? You claim the algorithm is objective, but this is a fallacy for a number of reasons. One, no "objective standard" was responsible for it's creation or design, only subjective criteria executed by an "object." There is no objective answer to what is "strict" or "lenient." So, even in that case, you still just have someone, or some group's, subjective valuation.
However, let's pretend that we are somehow in a format the is in the following state: 33.3% of top 8's are deck A, 33.3% are deck B, and 33.3% are deck C sustained over, lets say a year. Nothing else ever puts up results. Step one, what are we to make of this "format?" Should something be banned? Let us pretend, for the sake of this exercise, that A, B and C share no cards in common. So, what should have action taken on it? A, B, or C. How should we know, based off the data?
Lets take another case. Lets say our ban threshold is 80% sustained top 8 representation (whatever that means). What happens when something shows up 79.9% and sustains it? Is this a "good" format? Who knows, the algorithm doesn't care, it only takes input and renders output. If we round it, what happens if it is still just outside the "rounding" threshold? How close does "close counts" factor in? Why or why not?
Furthermore, to even construct this algorithm, but again we need to consider what the thresholds not only are, quantitatively, but what they serve, as a qualitative output. Because playing the game is not a quantitative exercise, it's a
qualitative experience. What good is a format that has been it's card appearance distribution statistically normalized that is no fun for anyone to play?
Is a format "fun" because statistically speaking, if no card shows up more than 24.67% of the time? What about 37.45% of the time?
So, yeah, maybe I'll buy your algorithmic approach if you could somehow answer how or why these aren't issues, or how they can be clearly addressed via an algorithm. I'd surmise that an algorithmic approach would inevitably make absolutely 0% of anyone happy, unless they actually don't care about playing the game and only care out the statistical output.
Sorry, but Dataism doesn't save us, just like creative narratives don't. In the end, it's still just a subjective process of valuation. Trying to fashion an algorithm on top needlessly (and pointlessly) formalizes it, serving literally no one's interest as far as I can tell. Unless, again, formal statistical information is all that matters. In which case, why play Magic at all?