You know, Charanam is a concept only unique to Indian music. A beautiful, short and sweet charanam goes a long way in making a fantastic song. Thanks for an interesting thread. Koil was a bit long, but IMO it can't be remotely even called a bad one. I can't understand why a charanam needs to be short to be good.
Udhaya observations are great.
I must say there was a point in time when IR's pallavi' irritated me when he used the algorithmic briding of the starting of the pallavi and anu pallavi. Only very few charanams were long-winded and pointless. However, ARR has more charanams that are irritating, but the innovative charanams are definitely just amazing ones than his pallavis. Hats of to both of them. Other music directors have also come up with unusual and exciting charanams, that include V Kumar, Rajen Nagendra and Vijay Bhaskar.