First, in terms of every fighting community in existence, it is the strongest and most complete ranking system. Ever. You can't even find a ranking system for most other communities because their data tracking isn't as evolved as ours. Heck, EVO does not post results past top 8! Let alone the bracket from every pool and full placement all the way down to last place.
Second, stock count would be meaningless. Game count? Might be worth something. But coming close would not increase the accuracy of any ranking system. Chess does not take into account how many pieces are off the board or how 'close' the game is. Again, taking into account games may be OK, taking into account how many stocks were lost? Terrible metric to every use for rankings.
Also, to be clear, I'm not trying to undermine the work that has been done on this system. It is widespread, well organized, and concise. Which is awesome.
With respect to the additional details that could be added, it depends on what kind of rankings you are looking at and how they were tabulated. In American Football (at least for college), the point difference in the game actually matters. This would be analogous to adding stock counts to our set data.
For fighting games, our ranking system's power may be true. I'll have to take your word for that. For video games in general, this is far from the truth. LoL, Starcraft, and even World of Warcraft have far superior systems. They, however, have the benefit of having far more data. Many of them hinge on an ELO type system, which in it's truest sense, takes a long time to converge on an appropriate player score. To compensate, they all share excellent online systems which are lag-less enough to allow their results to be indicative of relative player strength. This way, they can collect data every day, while we only get select in-person events to work from. Even then, we don't manage to collect all of that data.
A true improvement to our current system would probably require an overhaul at the website level. If putting the results for a tournament required entering cost numbers, the characters people used and so forth, that data could be mined automatically for further use. Heck, we could even go for the AiB thing and collect TIO brackets, since those are generally the most widely used.
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ANYWAYS. The original point is that using the rankings we have now for robust analysis should be taken with a grain of salt. While the effort is impressive and good for getting a general idea of who is placed where, I think it introduces enough error to mess up a statistical analysis.
This statement of it's ability to stand up to said analysis is just my opinion though.