There is no discussion, MK 2011 is canon. End of story.

One of the very few things we know about the plot right now is that Raiden's going to "screw up" and cause bad things to happen with his changes. There's so many potential outcomes of such a thing, where do you even start?

He could accomplish his goal of murdering Shao Kahn and, even though he's ruined the lives of a dozen characters, decide "Good enough" and move on, resulting in a sequel that continues directly from MK9.

Or he could cause the universe to be destroyed or Armageddon to happen even sooner.

Or he could accidentally cause Shao Kahn to win this time.

Or he could realize he's messing things up at some point and try to undo everything he did or make it so the message from the future was never sent.

So obviously, we can't actually discuss whether the events of the game's plot will still be canon by the time it's over or whether or not there can be sequels until we know how it ends.