Great post! Sri Lanka is one of the most underrated travel destinations from India. We had been there for 2 weeks and had a terrific time. (Non working vacation with family).
The people are super nice. Food is great and things are very affordable. Visa on arrival and all sites and tourist places are discounted for Indians due to SAARC. (Plus Sri Lankans generally are super nice to Indians over "other" asian neighbours).
We did Kandy, Galle and Sigiriya which were fantastic.
Actually if you are staying at a place with an international airport, it may even be more affordable to do Sri Lanka over Goa. (unless you are already in Goa).