I too felt the same about "Kaviri Maindhan". I was too enthusiastic about the Book when bought as I thought I am going to live again with the characters of "PONNIYIN SELVAN". But to my astonishment... (also Disappointment)
The total story plot was revolving around "Kanthamaaran" who was a trivial character in Ponniyin Selvan. Accepting him as a hero was undigestable. But as u continue reading as "Kaviri Maindhan" (alone not as a sequel to PS) it was quite normal to get accustomed along with the characters. "LOKA" a new character not even heard of in PS came into the picture. The LADY lead role which was occupied by too many stars in PS was given to a single girl ... this leaves a vaccum in the place where Kundavai, Nandhini, Vaanathi and Pooguzhali were involved.. not to mention much of Ponniyin Selvan also.. in PS Kalki used a singular naration for Ponniyin selvan not with much of a respect since he was small kid just in the growing stage. used to that kind of narration when we come to know him as PONNIYIN SELVAR.. made me get far away from him... not too close as he was in PS.
One sad thing to be shared .... not much of VANDHIYA THEVAN did in this "KM". No humorous adventures enjoyed by him (also us)....
But The work shud really be appreciated.. lot of involvement is needed.
Same as you, i had the doubt whether the "RATHINA HARAM" story was real (atleast to get along with history) or cooked up... can anybody clarify it??