In all seriousness, while I don't agree at all with most of what IGuessItsOver is saying, I do agree with the notion that K. Rool could be expected after Ridley's (and Daisy's) reveal.
Had somebody said that before Ridley's reveal, I would have had my doubts, but after Ridley, it did make sense for K. Rool to be revealed later.
Now, on the other hand, I'm gonna go out there and say that if you claim to have expected Simon or Richter without the leaks, then you're either just a revisionist historian, or a very lucky human being.
As for Chrom and DS, I'd say they were also unexpected, just not nearly as much as Simon and Richter. Especially Richter.
Chrom certainly caught me off guard. Honestly, if not for Richter, he would have been the biggest surprise, IMO. Though Simon would have been more surprising if not for the leaks.
Basically, for me, from biggest to smallest surprise factor, it was Richter > Chrom > DS > K. Rool > Simon.
Without leaks, Simon would be between Richter and Chrom.