Was talking to fellow hubber 'eagle' and he mentioned one interesting point about the prelude of 'kannai padithen'. He said that the instruments in the prelude try to sound like the voice and when the voices join in they try to sound like an instrument. So I heard the song again today and I must say 'eagle' was right!!! Do listen to the prelude of the song keeping this in mind and you will be pleasantly surprised.
This brings me to the observation that Usha always makes. That we are like blind men trying to describe an elephant. You think you have analysed everything in a Raja song and will be pleasantly surprised when someone comes up with a different POV.