I'm not sure we can say that yet. We don't have any real idea of which car is best. The Red Bull looks interesting, but the Ferrari does, too. At the moment all we can do is speculate, the testing doesn't reveal much other than whether the cars have reliability issues. I think we're all desperately trying to look for evidence of which cars are good and which are not, but with the new regs and no real racing done yet, it's just impossible to tell. We expect Merc and Red Bull to be amongst the best teams, but that's not a certainty.
I would guess that it is not really that weird to expect it to be between them. In fact I would guess that because of what happened last year, I am expecting Hamilton to be even more angry and would be doing even more insane stuff and risky stuff (which he keeps doing all the time but people ignore and thinks he is a clean driver, he was just because he was clean ahead of everyone, as soon as someone got close to him dude became dirty) which will result with him either being champion again very easily, or we are going to see something that would be like a horrible season because he will get point deductions, seconds penalties, and other stuff.