When Kingdoms of Amalur: Re-Reckoning comes to Switch, it'll be available fully on the cart in physical form.
Imagine that! You buy a physical product, and you don't need to download 5-10 GB of additional data to get it to work properly. While the jury is out on how stable this Switch port is going to be (amid some issues in the prior versions), one would hope that the extra months of delay between the initial release and the Switch version would garner some extra polish. Either way, the publisher states that the physical edition will have "the full game on the cartridge, no downloads are required."
Note, however, that the upcoming Fatesworn expansion (which is still wrapped up tight in terms of details) will require a download, because it's literally DLC. Still, having the complete original version on one cart will pay dividends years down the line. It's going to be very easy to get a Switch in the future given how many of them are in production, and 15-20 years on, even if the Switch eShop is dead and buried, you'll be able to pop the cart in and play.
Kingdoms of Amalur [Twitter]
