I agree with everything you say here. Originality is never widely accepted, otherwise I suppose it wouldn't be original.
Yet, most of Mika's detractors make the point that Mika is, in their opinion, anything but original: a 'thief', a copyist, a cut-and-paste rip-off artist, a bad Queen tribute act, Leo Sayer, all of that rubbish. Whereas, I can't see the reasoning behind any of that. To me, and to you, he IS original, not because he is making a revolutionary new form of music no-one has ever heard before, but because the sum of his parts adds up to something unique.
We can see that, but many can't, and probably never will. It doesn't anger me so much as it fascinates me, that opinion can be so divided.