this would require a wipe, which would piss everyone off extremely.
this would also be ridiculous right now because pvp is so broken. Playing the AI is more entertaining then pvp right now because of the huge delays between turns and the desync bugs that only happen in pvp. No matter what the high scores arent going to be accurate until all the bugs are fixed, so just dont worry about your score, it does nothing for you, Not to mention all the score hackers we get daily.
the game is still in beta, and i can see this change coming eventually, but not until pvp is fixed and beta is over.