Player rating for tournaments across all installments of Heroes.

I completely agree. But this will give stronger players the opportunity to pull ahead. And it will make this particular metric more significant, rather than a linear one. The number 3 was chosen based on the three prize-winning places, and to avoid increasing the leader's advantage even further. In principle, you could calculate the average result of the tournament and compare it to that. And the leaders would pull even further ahead. But that way, there wouldn't be any arbitrary numbers. We could try recalculating the tournament results, taking into account the average result, and see what comes out.