https://www.youtube.com/watch?v=CJEa6TnA824

As most fans expected, Qwark is narrating the events of the game from some point in the future. So, literally, the game is a retelling of the first game, as Insomniac said it was from day one. There is no new canon to worry about, as literally any changes can be taken as Qwark messing up his memories/Insomniac sneaking in later elements under the guise or Qwark. Either way, it confirms, again as Insomniac has done from day one, that the new game does not mean we'll get a new timeline for the franchise. 

The series doesn't really need a reboot, not like there's a lot you have to remember from the previous games to play a new one, you literally don't have to know anything about the series to play any of the games.

That last bit is a bit of a stretch when it comes to the Future saga, but mostly, yes, you are correct. Mostly because they almost always do a "last time on [X]!" to make sure you can jump right in. 

In recent games they've been going more and more the route of bringing back old stuff to enhance the world, though, and half of the point of this particular game is to retcon in some of the new stuff like the new species so that the franchise makes more sense, so that may not be the case for much longer. 

Only thing I can think that you really need to know is that Clank was kidnapped in Tools of Destruction going into Crack in Time, literally can't think of anything else anyone needs to know.  You don't need to know who Nefarious is since what he did in the pervious game is basically irrelavent.

Most of what he did in CiT is irrelevant too, if we're gonna be honest about it! He's just sort of there because they needed a villain. But that's neither here nor there. 

My point was, people were assuming that because of marginal differences we'd be getting a different canon and all of the past 14 years would've been a wash. Thankfully, that's not the case. As inconsequential as the physical ties between games generally are, it's better to keep going with it. Also, people need to learn how to read, since this is what Insomniac has been saying since day one and this game is still called a reboot. 

Ratchet and Clank has a story? I just blow shit up.