OK, everyone, here's another theoretical construct I'm going to toss out. I think parts of this are plausible, but I'm expecting vigorous rebuttals to help shape my views!
I come at this from the perspective of someone who (1) does Chinese music, and is deeply invested in it, but who also (2) is made dizzyingly happy by CM. I'm pretty convinced that my study of CM, however superficial, has changed my qin playing considerably, and that study of Indian music can rectify certain general deficiencies in Chinese music. (As to the matter of whether the exchange can go both ways, I'll have to wait to ask someone who's me in reverse--while I might be able to offer suggestions on how to 'improve' CM with Chinese input, that would really require the perspective of a CM insider.)
As we all know, Chinese music is characterized by the predominance of pentatonic scales--specifically the 'main five' transposible murchanas, viz. mohana, madhyamavati, hindola, suddha saveri, suddha dhanyasi. (Of course Chinese music doesn't follow raga grammar at all, so those are only basic approximations.) A discovery I think I've made over time is that there are both more and less effective ways to use a pentatonic scale. Here are my current theses:
(1) The most natural function of music is to express emotions, and heptatonic scales are the most natural means to do this. My biggest departure from traditional qin playing is the use of more heptatonic scales, since I feel like the emotional range of heptatonic scales is much vaster than that of pentatonic scales. Of course this intuition is well-developed in Indian music, where the 7-note scale is taken as 'basic' and 6, 5, 4-note (etc.) scales are seen as 'reductions' of fuller scales.
(2) It is possible to do really effective expression with reduced scales too, but not all reduced scales are created equal. I would argue that there are two kinds of reduced scales:
(2a) those that represent basically a weakening of a heptatonic scale, and
(2b) those that, through cunning omission, lead to an intensely new and interesting effect that the parent heptatonic scale does not accomplish.
A couple examples of each. Please forgive me if I get anything wrong: my knowledge of ragas is unsystematic. And again I'm talking more about melas than ragas here.
Kharaharapriya -> Suddha Dhanyasi is a relatively ineffective reduction. Suddha Dhanyasi feels like a weakened Kharaharapriya sequence.
Kharaharapriya -> Madhyamavati is a much more effective reduction. The omission of G2 and D2 removes the emotional immediacy of Kharaharapriya, leading to a curiously 'neutral' product. There's only one note diff between Suddha Dhanyasi and Madhyamavati (G2 vs R2), but it makes a big diff. Keeping G2 means that the 'negative' quality of Kharaharapriya is preserved, while omitting it leads to a product that is majestic in a more emotionally neutral way.
Hemavati -> Sarasvati is effective. The omission of G2 shows exactly how important G is in determining a mela's flavor; Sarasvati is much less 'negative' than Hemavati but preserves its slightly unstable and mobile flavor. The result is instability and mobility that are not so tied down by negativity, and which therefore seem freer.
From these examples I generalize:
(3) All reduction of heptatonic scales is a kind of 'neutralizing' of their emotional effect, but which notes you omit critically determines whether this neutralizing is just a weakening of the original effect or, much more desirable, an interesting new creation.
I know there are a lot of holes in what I've presented. I'd be very interested to see what people think, and to learn more examples that might support or discount what I've said.