The people that seem to be completely anti-re-review, I really don't understand. Applying singular review scores to a book or a movie and having that never change, well, fine, because that piece of work will remain the same throughout its lifetime. Modern games and the rise of DLC and online connectivity, though, necessitates changing the rules, because the package that a consumer is getting for their investment changes over time with these products.
On the other side, sure, if review sites want to go back and do the same for DriveClub or other games, I'd say they're more than welcome to do so. Admittedly I don't know the specifics of how games like that or Evolve have....evolved over time (bah), but speaking strictly for Splatoon's case I'd say the logic behind revising the review is completely justified. There are some distinctions that I think should be made in this case.
Popping Splatoon in to play today is a very different product than it was if you bought the game on day 1. The amount of content that's been added to the game is beyond substantial, the number of stages has more than doubled since launch, the amount of weaponry (including variants) is actually getting kind of ridiculous, there have been two large injections of new clothing with different ability combinations that give rise to the ability to craft new loadouts and looks, the number of actual game modes has doubled from 2 at launch to 4 now, and the addition of squad battles and private matches fundamentally changes the experience because they address two of the launch-game's largest criticisms. This isn't just a new mode, or a couple new guns, or a DLC map pack, the only aspect of the game's content that hasn't been doubled is the Octo Valley single player stuff, and there's still a chance for that to come down the line, too. Perhaps just as important as the content itself is the fact that all of this is
completely free and available to literally the entire player-base without any additional work on the player's part. You aren't going to see a re-review of CoD for the release of a paid map pack or season pass content finally coming out, because that content comes with its own additional cost and splits the player-base between those who continue to buy in and those who don't. This isn't the case in Splatoon, where the most recent version of the game, with all the additional content, is functionally
the only version of the game that exists, and all still for the original purchase price. That really hasn't been the case with most games, even games with the "gradual content roll-out" approach.
With Splatoon being one of the featured products as part of Nintendo's most recent Wii U bundles, I think it's a good idea to update the reviews, since people curious about the system will have a more accurate idea of what it is they're actually spending their money on. I don't know if re-reviewing will become a regular practice, if only because usually a game's business model isn't built in such a way that justifies it in the way Splatoon does. I'm personally going to be very curious to see how reviewers handle Street Fighter V, since the new fighters and maps and so forth that will be coming to that over time (and, at least theoretically, available without investing more than the game's original purchase price) create the next big example that I can really think of.