Can't serve something you don't have, tbone. Sure, the Comg chart points to a very good first week but you should have enough experience with Comg by now to know that the chart should be seen as a rough estimation and nothing more. Games have had terrible ratios before and it's not completely out of the question that Splatoon will end up with less sales than indicated. And that's just Japan. Where's the evidence showing that the game will do great across the globe? Because if it exists I must have missed it completely.
You should wait until we have some actual data, because all you're doing here is making a crow out of a feather and that often result in a pretty bad crow stew.