Before we start, I'd just like to mention a little bit about my musical background. I learned carnatic (South Indian ethnic) vocal at a young age, along with western classical piano. Eventually, I stopped singing (for various reasons I won't get into now), but continued steadily in western classical. In high school, I wanted to be a professional pianist, performing Beethoven and Bach. Around that stage, I'd listen to carnatic music and think "What? What are they doing?" (Although, I made it a point to attend at least one kacheri every Margazhi Mahotsavam). A lot of things about carnatic music really puzzled me. Since then, I've spent a lot of time comparing and contrasting the 2 art forms and understanding more about them. Which brings us to the blog at hand: I'd like to use this as an outlet to share what I've learned through all of this analysis.
No More Keyboard!
The piano is a western classical instrument, developed over the years to suit that particular style of music. I believe every instrument has something special to offer, and in the piano, it's polyphony: the ability to play multiple notes at once. The piano was designed like this to suit the requirements of western classical music, by allowing you to play 3 to 4 lines of music simultaneously. However Carnatic music does not allow this. Why do you want to waste such potential?
To make matters worse, you're not going to learn proper fingering or hand technique if you take carnatic lessons. Why? Unless your carnatic teacher knows how to play western classical, they're not going to have proper technique themselves. So not only are you wasting the instrument potential, you're also making your own life harder. There are over a dozen ways to play any given musical phrase, and the technique you use is what makes it easy or hard. In my opinion, anyone teaching carnatic on a keyboard is just out for a quick buck.
Let me just say, I'm not against playing carnatic on the keyboard every once in a while. If you want to, then by all means go ahead! Just be sure to learn western first, and then implement what you learn. Or, if you're composing fusion, then play western music on western instruments, and indian music on indian instruments! Why do you think Rajesh Vaidya's songs are so amazing?
What about Indian Instruments?
Indian percussive instruments are FAR more sophisticated than, say, drums, or even a timpani. In western percussion, you either hit a barrel drum on it's center, or it's rim. Deviating isn't going to produce a very different sound. Compare this with a mridangam or a tabla. The smallest deviation from the center produces a clearly audible variation in pitch, which enables virtuosos to demonstrate exactly how skilled they are!
This is again, why I would oppose implementing western music on Indian percussive instruments. Please be clear, I'm not saying "don't use a tabla in western music", I'm saying "don't play the tabla as if it's a timpani!" When you blend different styles of music, please let your instruments inherit their own musical customs. Remember, those customs are what define the instrument.
Update: December 27, 2014
For more info, read this article about K. Sathyanarayan.