Of course stereotypes can be positive (see the links provided). Either depending on the context or for the group overall. And, moreover, a stereotype doesn't come from nowhere. It's based on some factual truth.
So because some Asians aren't smart the fact Asians in general are seen as smart is bad for them? Why not see it from a different perspective : Asians that aren't so smart still benefit from the image that they are and may still get some advantage from it.
And you think there are no stereotypes about white people? Russians are alcoholics, latin people are ... etc.
I think you're using "white" to mean WASP.
You can't have it all : if they're praised for being studious and disciplined they can't also be seen as super nonconformists and rebelles... Both type of traits involve a different mental structure.
https://en.wikipedia.org/wiki/Halo_effect
https://en.wikipedia.org/wiki/Pygmalion_effect