Are Chinese native speakers more sensitive to tones or phonemes?
Yes. It is not unusual for native Chinese to have difficulties distinguishing between nasal vs non-nasal or alveolars vs retroflexed, but I have never met someone who has difficulties distinguishing between the 4 tones in Mandarin. Though I am learning Cantonese right now and for me, a native Mandarin-speaking Chinese the 6 tones of Cantonese is a little bit tricky. I can't answer if this is true with regards to all tone languages, just my observation. Hope it helps