To my mind Kalki's genius lay in his unparelleled sense of humor - in the midst of a serious story line, the dialogus between Azhvarkadiyan and VD, Ponnan - Valli in Parthiban kanavu, Gundodharan's self dialogue in SS, all bring smiles to face even when your read. Kalki was also a great social activist although he did try to cater to his conservative audience somewhat. His Savitri, Sivakami and Kalyani were very progressive women for their times. He tried to introduce rural characters as connected to royalty in a very natural way - spies, chariot drivers, boatmen, etc.
Anyone who has not read anything other than PS from among his work - you really do not know much of the real Kalki at all. Please do him an honor and read the other works with the open mind (Parthiban Kanavu, SS, Kalvanin Kaadhali, Thyaga Bhoomi..).
Yes very much so I agree on the humor part. It would be nice if modern novelists could add humor..well unfortunately humor is somewhat of a natural thing which a novelist has tod posess in addition to other qualities.Kalki had it naturally, many others may not.