Player rating for tournaments across all installments of Heroes.

You can tell that to yourself, smart guy. I answer all questions promptly. "Your idea is understood and will be considered." Ha ha ha, three times. Don't feed me empty promises.

Your idea has already been considered, and its absurdity has been clearly (and promptly) demonstrated. You've come up with another "brilliant idea," but read post 671. As in the previous case, it shows that it's not much better than the first one.
Are you talking about rating security again? Read the same post 671.
Your system is protected from clones (which wouldn't even make sense, except maybe in the fourth game, but due to the ability to view the game in progress, this needs to be done very carefully, i.e., it takes a long time), but it suffers from everything else just as much. And I'll add another question for you: how is your system going to prevent a player from cheating (someone takes and asks a friend to help them with a monster) or neutralize the effect on Tournaments in the fourth game of a certain cheat method, etc.
Tournaments are played for fun, and you shouldn't assume massive hardcore cheating.