Vijay, did not ask him about 'athisaya rAgam' because he had given the answer for that in a TV interview. It went something like.....KB had requested MSV for a tune based on a raga never used before. MSV bumped into Dr. BMK in AIR and communicated his predicament. BMK it seems responded stating that mahathi, his own creation could be a choice. Mahathi is a derivative of Harikambhoji mela kartha with only 4 swarams. This went against the 'Minimum 5 swarams' scheme and a verbal battle ensued between BMK and Veena S Balachander. athisaya ragam is a wholesome melody using 4 swarams and has traces of valaji. Lisen to the sitar pieces in the first BGM, followed by spurts of violin, flute and the sitar piece handover to the charanam. Lot of Valaji in it !!!!
Next time around, when he mentions his closeness to RD Burman, I will ask him about RDB using in Shaan, the core piece of the BGM in 'Ayirathhil oruvan' :)
One more area untouched, whenever he used ragas like Sivaranjani, the real face of Sivaranjani (that we wouldnt like to see, thanks for Laxmikanth Pyarelals, SA Rajkumars and Bharadwajs) remained suppressed. If ARR has re-tuned 'uthharavindi uLLE vA', we know what inspired him to use Sivaranjani for 'kaNNum kaNNum koLLai adithhAl'. Apart from 'uthharavindri uLLE vA' (which I thought was a masterful composition), enna vEgam nillu bhAma, poovA thalayA pOttA theriyum are songs which disfigure the true Sivaranjani (as mankind knows it).